[HN Gopher] Another scientific body has debunked bitemark analysis
       ___________________________________________________________________
        
       Another scientific body has debunked bitemark analysis
        
       Author : colinprince
       Score  : 237 points
       Date   : 2022-10-20 18:26 UTC (4 hours ago)
        
 (HTM) web link (radleybalko.substack.com)
 (TXT) w3m dump (radleybalko.substack.com)
        
       | boxed wrote:
       | Found a spelling/grammar/idiom error ("little to know" -> "little
       | to no"). Tried to commend, but I have to pay for that. Tried to
       | click to that persons profile. Have to create an account. This
       | seems like a bad idea...
        
         | cobaltoxide wrote:
         | > Tried to commend
         | 
         | ironic
        
       | ALittleLight wrote:
       | This seems like a really straightforward thing to test. If I get
       | a thousand people together, have them each bite 10 human skin
       | analogues, identify the participants and each of their bite
       | records with a GUID, can bite mark analysts map bite records to
       | biters and with what accuracy?
       | 
       | If they can't, why did the courts think they could? Why are we
       | doing the tests for whether or not a method works _after_ making
       | use of that method?
       | 
       | After skimming one of the papers linked in the NIST analysis - it
       | seems bite mark analysis is far below this standard. The analysts
       | being tested had substantial disagreements over whether something
       | was a bite mark and whether it was caused by adult or child
       | teeth. Matching bite marks to a reference mark seems well out of
       | reach.
        
         | chmod775 wrote:
         | > This seems like a really straightforward thing to test. If I
         | get a thousand people together, have them each bite 10 human
         | skin analogues, identify the participants and each of their
         | bite records with a GUID, can bite mark analysts map bite
         | records to biters and with what accuracy?
         | 
         | Not quite the same thing. Because that assumes you already know
         | it was one of those people.
         | 
         | More appropriately you should ask the labs "does this bite mark
         | fit any of these 100 people", where none of those people
         | actually caused the bite mark.
         | 
         | Will the lab recognize it was none of them? If they just
         | falsely identify one out of the hundred, that extrapolates to
         | millions of people.
        
       | umvi wrote:
       | > The field has a horrendous track record: More than two dozen
       | people arrested or convicted with bitemark evidence have since
       | been exonerated.
       | 
       | It's probably true that bitemark analysis is ineffective at
       | identifying biters, but I would appreciate it if the full data
       | picture were painted. 2 dozen people out of how many total?
       | 
       | It's like saying "X vaccine has a horrendous track record: more
       | than 50 people have died after receiving it". 50 out of how many?
       | If 200, that is indeed horrendous (25% death rate), but if 50
       | million, then it's not horrendous (0.0001% death rate). Let me be
       | the judge of what is horrendous or not by giving me full context.
        
         | PebblesRox wrote:
         | From the article, seems like only a few hundred cases:
         | 
         | "Bitemark analysis has been used only in a small percentage of
         | criminal convictions...At worst, it would require the re-
         | opening and reinvestigation of a few hundred cases.
        
       | WaitWaitWha wrote:
       | Good. I am not saying forensic ballistics is just as pseudo-
       | science, but it also needs a hard look to re-validate the
       | deductions and now-accepted methodologies.
        
       | gubernation wrote:
       | I had a feeling this research would come out. Just goes to show
       | what a disgrace Ted Bundy's trial was. We sanctioned the murder
       | of an innocent man and even televised his persecution.
        
         | the_doctah wrote:
         | What? Are you saying Ted Bundy was innocent? The guy who
         | escaped police custody and proceeded to the nearest sorority
         | house to bludgeon three girls to death in their sleep?
        
       | nova22033 wrote:
       | Proves the main thesis of his excellent book
       | 
       | The Cadaver King and the Country Dentist: A True Story of
       | Injustice in the American South
       | 
       | https://www.amazon.com/Cadaver-King-Country-Dentist-Injustic...
        
       | helloSirMan wrote:
       | So no way to be sure if I bought Jon Voights car?
        
       | skc wrote:
       | Heh, I used to watch true crime documentaries pretty religiously
       | at one point.
       | 
       | But the more I read about just how flimsy the science behind some
       | of these forensic techniques was the less comfortable I felt
       | until I pretty much stopped watching altogether.
        
       | 8f2ab37a-ed6c wrote:
       | I'd be curious to see a list of all of the classic cinema police
       | cliche's that have no basis in evidence. So far there's the lie
       | detector, blood spatter analysis, bite marks.. what else?
        
         | rincewind wrote:
         | hand-held laser speed measuring
        
         | hinkley wrote:
         | Tracking calls that are over 60 seconds.
         | 
         | Everything is electronic now. There are audit trails. It may
         | take a while to figure out where you were, but they will. So
         | the only advantage of getting off the phone early is to not be
         | there when the cops show up. And the fact of where you were and
         | what phone you used might help them identify you anyway.
        
         | SV_BubbleTime wrote:
         | Ballistic fingerprinting is almost completely nonsense as used
         | in media. Has some real life use, but limited.
         | 
         | There are multiple types.
         | 
         | 1. Capturing a spent casing and comparing to a reference of
         | that firearm. The idea being the primer indentation, and
         | chamber wall tolerances/imperfections should let you match
         | fired case to firearm. This was believed in so much that every
         | firearm sold in the past 20 or so years in NY/MD/?? has
         | required a spent case to be shipped with the gun and a case
         | kept at some crime labs, or the owner is required to provide
         | when registering the gun - the bullshit is that it doesn't work
         | at all - and not one single solved crime has ever been
         | attributed to this system. Giant waste of money / feel good
         | legislation. There is some correlation to be made... Factory
         | Glocks have fairly unique square firing pins and it's easy to
         | say a case was or wasn't fired from an _unmodified_ Glock.
         | Likewise, MP5 platform guns typically have fluted chambers and
         | one can easily see the case marks on a fired case, but neither
         | of these things will help with storing a sample.
         | 
         | 2. Muzzle/barrel printing. While this is a LITTLE more
         | scientific, mostly shit. For the most part, you need a really
         | large flaw in a barrel to leave a matchable print on the
         | barrel. You can look a fired bullet and easily tell the
         | rifling. Polygonal (Glocks again), cut, button, hammer
         | forged... but the whole microscope printing of miniature and
         | unique imperfections is a lot more art than science. Again,
         | easy to prove this bullet didn't / couldn't come from this gun
         | - but hard to prove it came from this specific gun.
         | 
         | 3. Micro stamping entirely bullshit. This is where a California
         | despite overwhelming evidence it doesn't work is still trying
         | to get firing pins to leave a unique impression on the primer.
         | The people that push for this stuff have no idea how guns work,
         | never have.
        
           | [deleted]
        
           | bjt2n3904 wrote:
           | Lived in MD. They did away with the spent shell casing law.
           | Turns out they were literally throwing them unorganized into
           | barrels. No way to organize or search through them if there
           | was a need. Just a massive waste of taxpayer money.
        
         | nonrandomstring wrote:
         | "The Lie Behind the Lie Detector" had a big impact on me [1].
         | As a kid I made lie detectors (a 9 volt battery, 1M-Ohm
         | resistor, BC108 transistor and buzzer) and got sent home from
         | school for "Interrogating" the other kids. The teacher
         | evidently thought it really worked - even though as an 8 year
         | old I knew it was just an electronic trick.
         | 
         | 40 years later the Iraqi government was purchasing thousands of
         | ADE 651 "bomb detectors" [2] - basically a stick - that no
         | doubt caused some poor dudes to get blown to bits by IEDs.
         | 
         | All technology (indistinguishable from magic) has a cult-like
         | aura around it, in that there's the reality of what it does,
         | and a separate set of human _beliefs_ about what it does.
         | Cybersecurity is full of wishful and magical thinking in this
         | regard. I sometimes feel like a kind of James Randi, trying to
         | debunk the _certainty_ people want and project on to
         | technologies.
         | 
         | [1] https://antipolygraph.org/lie-behind-the-lie-detector.pdf
         | 
         | [2] https://www.cnet.com/culture/divining-rod-reborn-as-
         | explosiv...
        
           | ghastmaster wrote:
           | Thank you. I had not heard of this product before. I want
           | one.
           | 
           | https://en.wikipedia.org/wiki/ADE_651
           | 
           | > According to Iraqi police officer Jasim Hussein, "The vast
           | majority of the people we stop, it's because of their
           | perfume". A fellow officer, Hasan Ouda, commented that "Most
           | people now understand it's what gets them searched, so they
           | don't use as much."
        
         | efficax wrote:
         | fiber analysis is also fake as hell (like saying: these threads
         | came from your carpet, or your shirt).
         | 
         | ballistic forensics only works if the gun is barely fired after
         | the time that the bullets in question are fired, becuase each
         | time you fire a gun it wears down the barrel again, in new
         | ways.
         | 
         | Fingerprint analysis is not based on solid science, nobody
         | knows how common it is for someone to have very similar
         | fingerprints to another person, and nobody knows what the right
         | standard for "points of similarity" is. Fingerprint analysis
         | has been used to convict people of crimes they could not have
         | committed because they were not in the same state or even
         | country, in ways that are provable:
         | 
         | https://en.wikipedia.org/wiki/Brandon_Mayfield
        
           | bornfreddy wrote:
           | Thank you for the link! Though I would say it highlights a
           | different problem (investigators' bias) than stated. The
           | Spanish police have rejected findings apparently.
        
           | WaitWaitWha wrote:
           | Forensics evidence is almost always circumstantial.
           | 
           | For your example - If everyone wears wool sweaters except one
           | person wearing poly microfibre, what is the inference?
           | 
           | The first rule that is taught in forensics is that every
           | interaction leaves a trace of some sort. The poly microfibre
           | showed up at the scene. How did it get there is now a
           | different type of forensics and where lawyers step in. The
           | prosecutor will insist because the poly microfibre owner was
           | there, while the defense lawyer will insist, there was a
           | party the night before and everyone was rubbing against each
           | other, the poly microfibre wearer and the wool sweater
           | wearers. It can be anyone.
        
           | thrdbndndn wrote:
           | > nobody knows how common it is for someone to have very
           | similar fingerprints to another person
           | 
           | Your last example is definitely a good counterexample to
           | this, but I feel in most of cases, the suspects are very few
           | so fingerprints only need to be able to distinguish one of
           | the others, than say, identify a random dude from billions.
           | So it's still useable.
           | 
           | It's like while SHA-1, or even CRC32, is totally incapable
           | for security, it's still perfectly fine to be used to detect
           | if a known file is corrupted (through natural cause, not
           | deliberately altered) or not.
        
             | jrochkind1 wrote:
             | That's like saying if a witness says "he had brown hair,
             | that's all I can say", and only one of "the suspects" had
             | brown hair, that's reason to convict him.
        
               | Eisenstein wrote:
               | You are misrepresenting the odds of a group of people
               | having an outlier hair color vs a group of people having
               | one which matches sufficiently well to a piece of
               | evidence which excludes the others.
               | 
               | 'I remember a brown car' vs "I remember a brown 1976 Ford
               | coupe with worn tires and a broken side window'.
        
           | derefr wrote:
           | > fiber analysis is also fake as hell (like saying: these
           | threads came from your carpet, or your shirt).
           | 
           | I'm not a forensic technician, but I've watched probably
           | every episode of every true-crime forensic documentary TV
           | show / YouTube channel / podcast / etc that exists; which
           | probably has some weak but non-negligible correlation with
           | having a gestalt impression of what people do and don't use
           | forensic techniques for in practice. (At least in the
           | "solved" cases, since the point of these shows is "how they
           | solved it.")
           | 
           | In every use of "fiber analysis" I ever saw covered, where
           | the "fiber analysis" was actually used to prove something,
           | the thing they're always noticing is "trilobal fibers" --
           | presumably because, at least for some period in recent
           | history, those type of fibers only ever got used by specific
           | manufacturers for specific use-cases (vehicle manufacturers,
           | for car floor matting, IIRC); and weren't part of the
           | composition of anything sold to individuals at retail
           | (except, perhaps, replacement car floor mats.) So "trilobal
           | fibers on the body" could be taken to imply "this person was
           | at some point in a car footwell/trunk."
           | 
           | I don't ever recall any case that made a "fiber analysis"
           | claim _other than_ that particular one. ( _Maybe_ once
           | someone claimed something about what proprietary dyes were
           | used on the fibers via GCMS assay -- but that 's not really
           | "fiber analysis" per se.)
        
             | giantg2 wrote:
             | I don't have a link handy, but there was a huge FBI scandle
             | where their experts were essentially calling things a match
             | to a specific person, etc.
             | 
             | But yes, the science is fine if interpreted correctly. The
             | correct phrasing would be exclude or not exclude a suspect.
             | Or for your example, it could be consistent with someone
             | having been in a vehicle. The problem is when the experts
             | say they _must_ have been in a vehicle, or especially a
             | specific individual vehicle.
        
               | Ekaros wrote:
               | That seems something that should be criminal. And
               | realistically always asked how many vehicles with this
               | type of material is there around?
        
               | WaitWaitWha wrote:
               | The judge should have thrown it out.
               | 
               | Second thing they teach in forensics is that unless I
               | witness the actual event, it is really hard to tie it to
               | a specific person. I can present dozens and dozens of
               | circumstantial evidence which has sufficient weight for a
               | reasonable person to make that inference, but I cannot
               | attest to that.
        
         | paradisechris wrote:
         | Fire pattern analysis often falsely claimed, from visual
         | analysis alone, that fires were started with an accelerant.
        
         | Ekaros wrote:
         | Body language experts... Thankfully I don't think it is used as
         | evidence, but still...
        
           | LtWorf wrote:
           | Think again.
        
         | duskwuff wrote:
         | Fire investigation was historically plagued by myths like
         | "concrete spalling means the floor was soaked in gasoline
         | before being set on fire". Turns out, concrete just does that
         | whenever it gets very hot, with or without an accelerant.
        
           | arrosenberg wrote:
           | Ironically, Law and Order SVU has an entire episode focused
           | on that issue.
        
           | aidos wrote:
           | This was posted years ago on HN and it has always stuck with
           | me.
           | 
           | https://www.newyorker.com/magazine/2009/09/07/trial-by-fire
        
           | eftychis wrote:
           | Oh
           | 
           | That was a thing? Was/is there any actual expert involved
           | ever in these claims?
           | 
           | I am more worried about all the claims that one field expert
           | can look at someone and tell if they are drunk, using
           | specific substances or had a head trauma. Doctors can't do
           | that but I guess... there are "experts."
        
             | knodi123 wrote:
             | Hell yes. A probably-innocent man in Texas executed for
             | murdering his family, based primarily on the evidence of
             | fire analysis which was later shown to be almost entirely
             | bullshit.
             | 
             | https://deathpenaltyinfo.org/policy-
             | issues/innocence/execute...
        
               | ghastmaster wrote:
               | > Ultimately, the authorities concluded that Willingham
               | was a man without a conscience whose serial crimes had
               | climaxed, almost inexorably, in murder.
               | 
               | This is what has condemned innocents throughout history
               | to death, torture, and prison. His history is what got
               | him convicted, in my opinion. So many people forget to
               | shield themselves from future indictment by acting
               | "normal" in the present.
        
               | eftychis wrote:
               | This is so sad in so many ways. I had to research the
               | topic and this was the first case popping up. Thank you,
               | and... I am still really sad...
        
             | duskwuff wrote:
             | > That was a thing? Was/is there any actual expert involved
             | ever in these claims?
             | 
             | Unfortunately, a lot of fire source experts were trained
             | based on a mishmash of folk theories about arson, many of
             | which have been subsequently disproven by scientific
             | testing. There have been some improvements over the last
             | decade or two, but the field is still heavily contaminated
             | by junk science.
        
         | av3csr wrote:
         | This report is relevant. If I recall correctly it pointed that
         | some of these analyses are not really reproducible.
         | 
         | https://www.ncjrs.gov/pdffiles1/nij/grants/228091.pdf
        
         | eftychis wrote:
         | You'd be surprised.
         | 
         | a) Drug recognition experts -- commented that on a sibling
         | comment too -- identifying drug usage vs e.g. trauma by sight.
         | 
         | b) blood alcohol levels imply alcohol consumption -- you could
         | actually be walking around with elevated alcohol levels not
         | realizing it due to liver issues+yeast biome/diabetes
         | (https://www.ncbi.nlm.nih.gov/books/NBK513346/)
         | 
         | c) uniqueness of fingerprints -- studies pointing always this
         | is a statistical argument not a unique identifier --
         | https://www.aaas.org/resources/latent-fingerprint-examinatio...
         | 
         | d) partial DNA match implying perfect match -- partial matches
         | have been used to convict people
         | 
         | e) probably every depiction of mental illness -- there are
         | exceptions but can't say Hollywood does its best there
         | 
         | f) lawyer interaction -- no your lawyer can't just barge in:
         | you have to ask specifically and probably persist on needing a
         | lawyer to consider any further interaction. (And even how you
         | word that is a minefield in the U.S.)
         | 
         | g) talking to the police -- somehow invoking the fifth is
         | something only bad guys do -- it is the other way around. And
         | that is causing issues already.
         | 
         | h) DNA, fingerprints imply you were there. No material can be
         | moved around. And police knows that. (And of course substances
         | too, e.g. you were in a tax/uber after someone exposed to X,
         | you are now exposed to X.)
         | 
         | i) pretty much all of statistics -- this case one would have
         | hoped would be the eye opener
         | (https://forensicstats.org/blog/2018/02/16/misuse-
         | statistics-...)
         | 
         | P.S. j) ... science honestly? I am always dumbfounded with how
         | much lack of basic scientific knowledge plagues courts and in
         | extend society. Courts can not survive with uncertainty: they
         | have to make decisions and stick to them. Science is different.
        
           | tinalumfoil wrote:
           | A lot of these problems come from deference to experts who
           | wear the hat of science. For instance,
           | https://en.wikipedia.org/wiki/R_v_Adams a man was convicted
           | because an expert said the DNA gave 1 in 200 million chance
           | of incorrect match (or something similar), which is
           | incorrect. I don't remember enough details to look it up, but
           | I recall a US case where the prosecution repeatedly used an
           | expert with a history of lying on stand and of course people
           | wrongly spent time in jail for that.
           | 
           | I think a bigger issue here, at least in the US, is
           | prosecutions seems to have a really easy time finding
           | experts, often on the same payroll as the prosecution, who
           | say the things needed to get a conviction and jurors are
           | encouraged to blindly trust that.
        
             | vkou wrote:
             | That's the whole point of the adversarial system. The
             | prosecution finds experts that state one _opinion_ , the
             | defense finds experts that say a contrary _opinion_ , the
             | juries pick out whose _opinions_ they want to believe. That
             | 's the whole point of expert witnesses - they are the only
             | witnesses in the courtroom who are there for their
             | _opinions_.
             | 
             | The problem is that one side of this equation has a cottage
             | industry of well-funded experts to pick from, but there
             | isn't a cottage industry of well-funded 'bullshit
             | debunkers' to work for the defense.
        
           | the_af wrote:
           | > _g) talking to the police -- somehow invoking the fifth is
           | something only bad guys do -- it is the other way around. And
           | that is causing issues already._
           | 
           | The "don't talk to the police" video has been shared enough
           | times on HN that I know I will never do so, at least in the
           | US. The video claims you are likely to incriminate yourself
           | and be charged with something _even if you didn 't commit the
           | crime the police is investigating_!
        
         | JoeAltmaier wrote:
         | Wait - blood spatter must follow the rules of physics, so there
         | is _some kind_ of analysis that would be valid, surely?
         | 
         | Reading online I see its still respected lots of places and
         | still taught in forensics. Don't know where that came from.
        
           | agf wrote:
           | I think if you read this article you'll see (at least part
           | of) the answer. Not only does a given action have to cause a
           | definable result, the medium upon which the result is
           | deposited has to provide enough detail to read the result
           | back off it, and the people reading the result have to be
           | able to be consistent and accurate in their analysis of that
           | result.
           | 
           | With bite marks, the skin has to hold the bite mark (which it
           | doesn't) and experts have to be able to map it back to real
           | human teeth (which they can't). With blood spatter, there are
           | analogous problems.
        
             | JoeAltmaier wrote:
             | Which sounds miles from 'have no basis in evidence'. So
             | that might have been a little hyperbolic.
        
               | snapcaster wrote:
               | I'm not sure why you're trying to play devil's advocate
               | on that. The things they are claiming about the analysis
               | techniques literally have no basis in evidence. Saying
               | "blood spatters follow laws of physics" has nothing to do
               | with what the experts are doing now
        
               | JoeAltmaier wrote:
               | ...and I countered with "the physics surely have
               | validity", which the plentiful science done to date has
               | corroborated.
               | 
               | Not playing devil's advocate; just doing some simple
               | searches and calling out hyperbole.
               | 
               | These days folks have replaced science with advocacy. You
               | know, that thing lawyers do to convince a jury. To the
               | point folks think that you can arrive at a conclusion
               | with advocacy. Instead of looking at the data.
               | 
               | I'd ramble on about how the world is going to pot,
               | because folks thing a sarcastic remark or clever-sounding
               | turn of phrase is 'just as good' as facts. But oh well.
        
               | kortilla wrote:
               | You confused the GP statement about "blood spatter
               | analysis" with a statement about "blood spatter".
               | 
               | If someone critiques astrology you don't reply that
               | "planets follow physics".
        
               | snapcaster wrote:
               | "Blood spatter analysis" is not a physics based
               | discipline. The other comment responding to you with the
               | analogy about astrology is good explanation of what is
               | wrong with your reasoning
        
               | ouid wrote:
               | not so, if i square a number, and get 4, There is no
               | basis in evidence for the claim that the number I squared
               | was 2. it could equally likely have been -2. Science is
               | capable of making no stronger a claim than that.
        
           | DSMan195276 wrote:
           | I mean the Wikipedia article on it basically says as much:
           | https://en.wikipedia.org/wiki/Bloodstain_pattern_analysis
           | 
           | > The validity of bloodstain pattern analysis has been
           | questioned since the 1990s, and more recent studies cast
           | significant doubt on its accuracy. A comprehensive 2009
           | National Academy of Sciences report concluded that "the
           | uncertainties associated with bloodstain pattern analysis are
           | enormous" and that purported bloodstain pattern experts'
           | opinions are "more subjective than scientific." The report
           | highlighted several incidents of blood spatter analysts
           | overstating their qualifications and questioned the
           | reliability of their methods. In 2021, the largest-to-date
           | study on the accuracy of BPA was published, with results
           | "show[ing] that [BPA conclusions] were often erroneous and
           | often contradicted other analysts."
           | 
           | That's not the same as saying it could _never_ be done
           | properly, but the analysis being done right now is not that,
           | even though it's presented in courts as expert opinion with
           | high certainty.
        
           | d1sxeyes wrote:
           | I think the key challenge to blood spatter analysis is not
           | that there's _no way_ it could be valid, it 's that so far,
           | it's based primarily on unsupported assumptions and
           | statements. Those assumptions may well be correct, but the
           | hard physics behind it has not been done yet, it's been just
           | folks saying 'well I'm very clever and this is what I think'.
        
             | JoeAltmaier wrote:
             | An internet search shows there is research done,
             | particularly the 'hard physics' behind it..
        
               | meheleventyone wrote:
               | Is there? Simulating forward sounds doable. Some fluid
               | sprayed from here, with this mass and so on it lands as
               | so. Backwards from a spatter pattern on an object sounds
               | a lot harder, not least because there will be multiple
               | possible answers and heaps of unknown variables.
        
           | [deleted]
        
           | etempleton wrote:
           | Blood splatter is still studied. What I think most forensic
           | experts would tell you is they are really trying to compile
           | as much evidence as possible that allows the largest
           | reconstruction of what may have happened. It is not like the
           | movies, or it shouldn't be, where you find a single finger
           | print and that determines who the killer is.
        
           | cool_dude85 wrote:
           | Everything follows the rule of physics. The existence of some
           | way to do something is a very low bar to clear. There may be
           | some way to determine if there's water underground, but that
           | doesn't mean a dowsing rod can.
        
         | giantg2 wrote:
         | Many things do have a basis in science. The main problem (with
         | almost all of them) is that the results are interpreted in
         | incorrect ways. For example, you can compare hair and fibers
         | just fine. You cannot say it's a match. You can only tell if it
         | excludes or does not exclude someone. Yet many experts would
         | say it's a "match" and the juries believe it's unique to the
         | suspect.
        
         | cscheid wrote:
         | From my understanding, fingerprint analyses don't have widely-
         | accepted specificity or sensitivity rates either. Those "73%
         | match" figures are not derived from any sound principles.
        
         | LtWorf wrote:
         | This presents a summary of all the bullshit science.
         | 
         | https://www.youtube.com/watch?v=ScmJvmzDcG0
        
         | TotoHorner wrote:
         | Breathalyzer tests are incredibly inaccurate and prone to
         | false-positives.
         | 
         | Not saying they have no basis in evidence, but people
         | drastically overestimate their accuracy.
        
           | Ekaros wrote:
           | And that is why they should only be for suspicion and any
           | real evidence should be from blood test administered in
           | suitable location verified in lab.
        
           | JoeAltmaier wrote:
           | They have an accuracy rate that is pretty good. Sure they
           | have false-positives (eat a gas station pizza, ping positive)
           | but far more likely are false-negatives due to bad air
           | sampling. Folks go to all sorts of extremes to fake them in
           | the car-installed devices e.g. have somebody else blow; blow
           | through a long tube so the sample is just what's in the tube;
           | hold it out the window and let the wind 'blow' into it; put
           | two straws into a half-full drink cup, blow into one and
           | connect the device to the other, and on and on.
           | 
           | The devices have all sorts of countermeasures now including a
           | dash-cam, temperature sensors, humidity sensors etc to try
           | and ensure its actually the right human's breath.
        
             | TotoHorner wrote:
             | "Pretty good" is completely unacceptable if states will
             | suspend your drivers license for 12 months if you refuse to
             | take the breathalyzer test (many states do this).
        
               | kelnos wrote:
               | Yeah, it's gross that consent to a breathalyzer test is a
               | precondition for even getting a license in the first
               | place.
               | 
               | Are people convicted of DUI based on breathalyzer
               | evidence alone? I would hope that the breathalyzer is
               | just used as a first gate (since it's relatively easy to
               | administer), but then a conviction would require
               | corroboration from a blood test. Then again, with our
               | "justice" system as it is, I wouldn't be surprised if a
               | breathalyzer is enough in some circumstances.
        
               | deepspace wrote:
               | > Are people convicted of DUI based on breathalyzer
               | evidence alone?
               | 
               | In some jurisdictions, absolutely
        
               | kkielhofner wrote:
               | > Are people convicted of DUI based on breathalyzer
               | evidence alone?
               | 
               | Yes and no. In the US the DUI process looks like this
               | (it's an interest of mine):
               | 
               | 1) Pattern of impaired driving or other reason to justify
               | the stop. This one is ridiculous and of course highly
               | subjective - it includes things like a "sweeping turn"
               | which is essentially not turning into the closest lane of
               | traffic on a turn (think left turn and not turning into
               | the left most lane), tires brushing a line, etc. Then
               | obviously there's speeding, running stop signs, etc. In
               | some states DUI checkpoints are legal where courts have
               | ruled (essentially) that the Fourth Amendment doesn't
               | apply for one reason or another to blanket stops for
               | investigating impaired driving.
               | 
               | 2) Some justification to start or continue a criminal
               | investigation beyond the justification for the stop -
               | this is the classic/infamous template: slurred speed,
               | bloodshot/watery eyes, smell of alcohol, etc that you see
               | in literally every single police report for impaired
               | driving.
               | 
               | 3) Field sobriety tests (FSTs). These are designed for
               | you to fail and completely ridiculous. In the era of dash
               | and body cams you're essentially going to put on a
               | horrible performance that makes you look intoxicated or
               | at least ridiculous even if you aren't. It's been
               | demonstrated time and time again these tests are
               | subjective and failure prone under ideal controlled
               | conditions with known factors, let alone someone suddenly
               | pulled out of their car on the side of a dark road
               | somewhere...
               | 
               | 4) Preliminary breath test (PBT). This is the small,
               | roadside, handheld unit. You're usually going to get this
               | no matter what. Obviously if this reports above the legal
               | BAC limit you're going to get arrested. Depending on a
               | variety of factors (how the officer feels, your FST
               | performance, etc) you can be arrested for impaired
               | driving regardless. This is obviously to account for
               | other drugs that impair driving but of course do not
               | register on an alcohol test. Additionally, you can be
               | under the legal limit and still get arrested for impaired
               | driving for the real/suspected "I had a beer but I also
               | took a bunch of Xanax" type situations. To my knowledge
               | these results are not admissible (or easily defeated) in
               | court.
               | 
               | 5) Certified test. When you get down to the police
               | station (or wherever) they're going to have you do a
               | breath test on a "certified" machine that's supposedly
               | tested, calibrated, etc. Interestingly, in most places
               | there are two tests, typically spaced by 20 minutes (or
               | so). Apparently this is to account for the
               | surface/residual alcohol issue. If you swish Listerine
               | around your mouth and blow into a breathalyzer it will
               | max out and tell you you're dead (essentially). Yet
               | obviously none of this alcohol is in your blood. My
               | understanding is for most cases the second reading is
               | emphasized/reported/charged even though it's almost
               | always lower because it eliminates a "residual alcohol"
               | defense and the result is typically far over the legal
               | limit anyway. This test is defined as "scientific" and
               | admissible in court.
               | 
               | Of course in many cases where a breath test is refused or
               | other drugs are suspected they can get a warrant for
               | blood. Typically the barrier here is having a judge on
               | call at 2 AM (or 10 AM, whenever) with a rubber stamp to
               | issue these. That said, most places with DUI checkpoints
               | now will have judges at the ready so more and more a
               | refusal to do FSTs or a PBT at a checkpoint is signing
               | yourself up for an almost instant blood draw.
               | 
               | But, to answer your question there have almost certainly
               | been people convicted on breathalyzer evidence alone.
               | However, "convicted" is a stretch here because to my
               | knowledge there aren't a lot of jury trials for DUI -
               | it's just not really worth it to anyone because the
               | stakes for either side aren't really that high. Besides,
               | in many states the Department of Motor Vehicles or
               | whoever controls licensing has a completely separate
               | administrative process that applies to your driving
               | privilege.
               | 
               | I suspect in many cases where a breathalyzer has been the
               | sole evidence even many (most?) innocent people will
               | plead to "reckless driving" or whatever the prosecution
               | offers - especially because in most places there isn't
               | jail time for a first offense regardless, most states
               | have some kind of hardship/occupational standard in place
               | so that you can still drive for work, school, worship,
               | child care, etc, and as mentioned the DMV process is
               | somewhat separate anyway.
               | 
               | Because of the car-first culture in the US (vast
               | distances, limited/non-existent public transportation,
               | costs of ride sharing, etc) many people just drive with
               | suspended licenses anyway which, to get back on track
               | with tech here on HN, isn't what it used to be. ALPRs
               | (automatic license plate readers) have really changed the
               | game there.
        
               | ajsnigrutin wrote:
               | This depends on the country.
               | 
               | In mine (slovenia, a lot of drunk people here), you can
               | not-sign the agreement with the breathalizer result, and
               | the police will take you to a clinic to do a blood test.
               | Usually breathalizers show a bit less (larger
               | tolerances/errors that the police have to subtract from
               | the measured result), but if you're big/heavy enough, and
               | the nearest clinic is far enough, it might be worth it,
               | since you'll process some of the alcohol in the time to
               | get the blood taken... depending of course if you're on
               | the upper limit to a higher fine or near the lower limit.
        
               | [deleted]
        
         | iudqnolq wrote:
         | You want the book _Junk Science and the American Criminal
         | Justice System_ [1] by Chris Fabricant, the Innocence Project
         | 's Director of Strategic Litigation.
         | 
         | The book is an approachable, anecdotal tour of some of the
         | significant issues with each major sub-speciality within
         | forensic science.
         | 
         | The Innocence Project uses DNA testing to prove convicted
         | criminals are actually completely innocent of everything, them
         | undergoes the massive legal battle required to have a chance of
         | going from conclusive evidence of innocence to release in the
         | American Justice System. The are reasonable quibbles with their
         | methods on the margin, but taken as a whole their work is an
         | amazing contribution to society.
         | 
         | Edit: I imagine some people might be skeptical that there's an
         | uphill battle after conclusive evidence of innocence. Take a
         | look at Shinn v Ramirez. Mark Brnovich, the Arizona Solicitor
         | General, successfully convinced the Supreme Court to tell a
         | federal judge they couldn't look at Ramirez's evidence he's
         | innocent. Notably Brnovich said "innocence isn't enough here"
         | [2][3].
         | 
         | [1] https://www.amazon.com/Science-American-Criminal-Justice-
         | Sys...
         | 
         | [2] https://deathpenalty.org/innocence-isnt-enough-here-
         | arizona-...
         | 
         | [3] https://www.scotusblog.com/case-files/cases/shinn-v-
         | ramirez/
        
         | muaytimbo wrote:
         | handwriting experts?
        
         | bolangi wrote:
         | Fingerprint analysis is rather sketchy, convicting someone
         | based on a tiny part of a print. Also lie detector analysis.
        
         | codeflo wrote:
         | Lots of scandals around DNA evidence as well. It's not the
         | science itself that's wrong, but mistakes can be made and were
         | made during collection and in interpretation.
        
           | amenghra wrote:
           | There's also cases of people who received a transplant who
           | then supposedly have two (or more) different DNAs in their
           | blood.
        
             | kstrauser wrote:
             | It also turns out that chimerism may be a lot more common
             | than we'd thought.
        
             | throwaway894345 wrote:
             | Wow, that's pretty crazy. I never really thought about how
             | transplants imply two different sets of DNA cohabitating in
             | the same body.
        
               | neaden wrote:
               | I think the relevant transplant is bone marrow, since
               | that produces Red Blood Cells. Here is an article about
               | it:https://www.nytimes.com/2019/12/07/us/dna-bone-marrow-
               | transp...
        
           | knodi123 wrote:
           | Wasn't there a famous incident where the police assumed they
           | were dealing with a serial killer because identical DNA was
           | found at dozens of crime scenes, and only much much later did
           | they learn it was the DNA of a guy who worked at the DNA
           | analysis lab who didn't always wear gloves like he was
           | supposed to?
        
             | nebalee wrote:
             | Sounds similar to this:
             | https://en.wikipedia.org/wiki/Phantom_of_Heilbronn
        
           | LtWorf wrote:
           | Nowadays DNA is matched by a proprietary software that nobody
           | knows if it's buggy or not. But I've never seen a non buggy
           | software before...
        
         | glenstein wrote:
         | This was my first thought as well. I think penmanship analysis
         | is a candidate.
        
           | googlryas wrote:
           | There are two types of handwriting analysis - "Graphology"
           | and forensic handwriting analysis. Graphology claims to be
           | able to derive personality/psychological traits of the
           | penman, and is just for charlatans. But, forensic handwriting
           | analysis is "real" and useful, for determining if a known-
           | author handwriting sample matches an unknown-author
           | handwriting sample.
        
         | monocasa wrote:
         | Hair analysis is another. Famously, a man was convicted based
         | on hair at the scene that turned out to belong to a dog
         | instead.
         | 
         | https://splinternews.com/the-fbi-convicted-this-man-using-ha...
        
         | DubiousPusher wrote:
         | If only it was limited to the cinema.
         | 
         | https://www.washingtonpost.com/local/crime/fbi-overstated-fo...
        
       | 2bitencryption wrote:
       | I've been listening to the podcast Your Own Backyard (yes, I
       | occasionally indulge in true crime, sue me!)
       | 
       | There was recently an entire episode dedicated almost entirely to
       | cadaver dog testimony. Well, the dog was not testifying, the
       | handler was.
       | 
       | Now, I have no doubt that cadaver dogs can, and do, find
       | cadavers, and can detect when a cadaver was recently present.
       | 
       | But listening to the testimony of the handler, from their
       | viewpoints, the cadaver dogs are _psychic_. The ability of their
       | senses verges on mysticism.
       | 
       | I don't doubt that there is value to cadaver dogs - clearly they
       | work, and get results. But the humans who testify on the dogs'
       | behalf have a cult-like behavior about what the dogs can
       | realistically detect, and how they interpret the dogs behaviors.
        
         | asveikau wrote:
         | > (yes, I occasionally indulge in true crime, sue me!)
         | 
         | Sounds like civil court rather than criminal.
        
         | ghastmaster wrote:
         | Similarly, handler beliefs affect scent detection dog outcomes
         | to at least some degree as indicated in this study:
         | 
         | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3078300/
         | 
         | > No conditions contained drug or explosive scent; any alerting
         | response was incorrect
         | 
         | > Within marked conditions, handlers reported that dogs alerted
         | more at marked locations than other locations.
         | 
         | > The overwhelming number of incorrect alerts identified across
         | conditions confirms that handler beliefs affect performance.
         | Further, the directed pattern of alerts in conditions
         | containing a marker compared with the pattern of alerts in the
         | condition with unmarked decoy scent suggests that human
         | influence on handler beliefs affects alerts to a greater degree
         | than dog influence on handler beliefs
         | 
         | I found this to be very telling. It at the very least warrants
         | more study. At the worst and in my opinion, warrants
         | elimination of dog scent detection as the sole factor in a
         | search.
        
           | wsc981 wrote:
           | A bit similar in the story of the counting horse from Germany
           | in the early 20th century:
           | https://en.m.wikipedia.org/wiki/Clever_Hans
        
           | rozab wrote:
           | Check out this article from the National Detector Dog
           | Association - 'The Double-Blind Attack'. These people
           | seriously don't believe in science.
           | 
           | https://nndda.org/the-double-blind-attack/
        
             | MereInterest wrote:
             | Wow. Everything in that article reads as an admission that
             | canine units are utterly useless, even as the article tries
             | to defend their use. The primary argument seems to be that
             | dogs need constant and immediate reinforcement in order to
             | be effective, and therefore double-blind studies are not
             | effective measurements. This same argument would also imply
             | that canine units are not effective in the field, since the
             | handler wouldn't be able to provide accurate reinforcement.
        
             | ghastmaster wrote:
             | Wow!
             | 
             | > Results in confusion and frustration in the canine - As
             | stated previously, under doubleblind testing, the
             | determination of the team's accuracy cannot be made at the
             | time of the alert. Therefore, to provide or withhold a
             | reward from the canine under such a condition can result in
             | confusing and frustrating the canine, which will lead to an
             | increase chance of incorrect responses.
             | 
             | Juxtapose that with the real world. I am not an expert but
             | I sincerely doubt that K9s in airports get treats every
             | time they correctly identify a illicit source. That is why
             | they are trained constantly(I presume). Testing for one
             | hour or one day will likely not have an effect on the long
             | term ability of the dog to correctly sniff illicit sources.
             | 
             | The NNDDA article is addressing the "double blind attack",
             | which in my opinion is their way of redirecting from the
             | notion that the K9s _should not_ be used as a gold standard
             | to ascertain probable cause. I would have to think more on
             | the subject to comment on reasonable suspicion. If they
             | truly believed in the idea that handlers are benign, they
             | would embrace the double blind process.
        
               | Eisenstein wrote:
               | Reminds me of audiophiles. When the scientific method is
               | the enemy, you are dealing with some massive
               | psychological effects that people refuse to acknowledge.
        
         | bee_rider wrote:
         | I would be fascinated to know how many and to what extent
         | police techniques that appear to stretch believably are really
         | tools to perform parallel reconstruction and get around shady
         | sources of evidence.
        
           | rnk wrote:
           | Probably a lot of them. The US justice system has a lot of
           | good things, but parallel reconstruction, constantly using
           | the easiest way to get info even if it is illegal. Of course
           | the latest thing is spying on all of us either through apps
           | on our phones or just asking the phone company directly.
        
         | giantg2 wrote:
         | "... and how they interpret the dogs behaviors."
         | 
         | The interpretation part is huge in many disciplines. If you
         | especially look at high profile cases, you can have experts for
         | each side presenting opposing interpretations (not even
         | involving animals).
         | 
         |  _Then it 's up to the jury to decide which is more
         | believable._
         | 
         | There's your spooky story for the day.
        
           | lcnPylGDnU4H9OF wrote:
           | And, unfortunately, "reasonable doubt" is not a reliable
           | fallback in such a situation.
        
           | FpUser wrote:
           | So it seems that "beyond the reasonable doubts" is a fiction
           | unless one can afford really expensive lawyers.
        
         | TheSpiceIsLife wrote:
         | _Some of the humans_ , the subset who's testimony was selected
         | to appear on that show.
        
         | JacobThreeThree wrote:
         | The entire industry, yes industry, of "expert witnesses" is
         | murky.
        
         | jessaustin wrote:
         | A cadaver dog could be useful for _finding_ a carcass, human or
         | otherwise. Once a carcass is found, can 't more qualified
         | experts testify about it? Are we talking about cases in which a
         | carcass _wasn 't_ found, but was theorized to have been present
         | at some point?! How do we know the carcass was human? How do we
         | know how long ago it was present? If we could be certain of
         | either of those things, how do we know it was the particular
         | human whose murder is being prosecuted?
         | 
         | We can't blame dog enthusiasts for testifying, but it's a
         | judge's job to keep fantasists out. Judges who allow such
         | testimony aren't stupid; they are evil.
        
           | ouid wrote:
           | well, one potential nefarious use of dogs is the parallel
           | construction of evidence that was gathered illegally in some
           | way. That's, I assume, what psychics are for.
        
           | bombcar wrote:
           | When they find a body, it's easy.
           | 
           | It's the cases you'll read about when it says the dog
           | "activated" or "altered" five times on the property, even
           | though nothing was found, and that's somehow used as evidence
           | of something.
        
             | P5fRxh5kUvp2th wrote:
             | That scares the shit out of me if I'm being honest.
             | 
             | years ago I read an article by bruce schneier talking about
             | how he ran an open home network so if someone accessed
             | illegal content he could claim it could have been anyone.
             | His argument was that if it was secured the police would
             | argue it had to have been him.
             | 
             | I got the point but disagreed.
             | 
             | a year or two later I was reading an article about a police
             | officer that got convicted of accessing child pornography
             | on the police computer systems. The chief of police was
             | quoted as saying "we know it was him because he used his
             | password".
             | 
             | My ass went home that night, opened up my home network, and
             | I've ran it that way ever since.
             | 
             |  _of course_ it 's not that simple, understanding why that
             | chief of police was wrong (I'm not making any claims about
             | whether that police officer did or didn't access that
             | material) in his confidence is what caused me to suddenly
             | strongly agree with Bruce Schneier.
             | 
             | So when I hear things like your dog story, I just know that
             | confidence has to be misplaced, even if I don't fully
             | understand why (although in this case I do).
        
               | rnk wrote:
               | Those aren't really the same thing. You can go to the
               | next level of detail on the password question. Was the
               | officer reliably in the area, was his password well
               | known, is it trivial for anyone to find the password.
               | Whereas wifi at your home, there are endless ways to get
               | it, plus did you share it with anyone.
        
             | MereInterest wrote:
             | Or, when a dog's "evidence" is used to get a warrant. The
             | argument is that the right to privacy does not exist for
             | illegal actions, and a dog will only alert for illegal
             | contraband. So a baseless fishing expedition without any
             | reasonable justification is rendered legal based on
             | pseudoscience.
        
             | jessaustin wrote:
             | That's hideous. Judges who allow that testimony should be
             | impeached and disbarred, at a minimum.
        
               | vkou wrote:
               | I don't see why judges can't allow bunk testimony, the
               | problem is that juries have been watching way too much
               | CSI:Miami and don't believe any arguments brought up by
               | the defense that forensic 'experts' are reading chicken
               | entrails.
        
               | MereInterest wrote:
               | For the same reason that a defendant may not be presented
               | to the jury in handcuffs or in a prison uniform. Because
               | we humans are not able to return to a blank slate, free
               | from biases imparted by information later learned to be
               | false. For methods that are known to be useless, the jury
               | shouldn't be asked to perform the impossible.
        
               | usefulcat wrote:
               | Easy to say. But to the extent that it's easy to get rid
               | of judges they can't be an effective check on the other
               | branches.
        
             | iudqnolq wrote:
             | There's also "dog alerted, after five days of digging we
             | found a single bone fragment 200ft away. Insufficient DNA
             | remains for us to conclusively say it's human, but all the
             | evidence is consistent with human"
        
           | phpisthebest wrote:
           | This is like saying "Dont hate the player hate the game"
           | 
           | No I am perfectly capable of rightly placing blame on both.
           | In this context the Cops, prosecutors and judges all have an
           | ethical duty to the truth. All 3 seem to have forgotten that
           | underlying obligation in the system
           | 
           | They want that "win", that conviction, that revenge, or what
           | ever.
           | 
           | So yes I will blame the judge for letting bad "evidence" in
           | that lacks proper foundation, but I will also blame the cop
           | that is presenting the "evidence" and the prosecutor that
           | presented the "evidence"
           | 
           | Our systems have layers for a reason, we can not and should
           | not have to relay solely upon the Judge as the first, last
           | and only line of defense here.
        
             | CoastalCoder wrote:
             | > In this context the Cops, prosecutors and judges all have
             | an ethical duty to the truth. All 3 seem to have forgotten
             | that underlying obligation in the system
             | 
             | Could you clarify: are you referring to every single member
             | of those 3 groups, or just some?
             | 
             | And if it's just some, then roughly speaking, what fraction
             | do you mean, and what evidence supports that?
        
               | phpisthebest wrote:
               | Depends on which part of that quote...
               | 
               | I believe every single member of all 3 have an ethical
               | duty to the truth
               | 
               | I think a significant number of all 3 groups have
               | forgotten that, or believe something else take precedent
               | further I believe every member of all 3 groups knows
               | about a co-member of the group that has ignored or
               | violated their ethical duty and looked the other way, or
               | actively covered for that abuse
        
             | paperwasp42 wrote:
             | I think it's important to note that cops, prosecutors,
             | judges, etc. are trained and encouraged to "listen to the
             | science" and "don't rely on your gut." Of course, many
             | disregard this, due to corruption or other moral failings.
             | But many _do_ follow this advice, and sometimes it results
             | in presenting faulty evidence simply because they have been
             | taught faulty science.
             | 
             | In addition to rooting out corruption and dismantling
             | immoral incentives, we need to seriously re-examine the
             | forensic science that is the backbone of many cases. People
             | --including judges, juries, cops, and lawyers--are far too
             | willing to blindly trust "science," and it can have
             | extremely scary outcomes. We need more replication of
             | studies and better science education for our criminal
             | justice professionals.
        
               | phpisthebest wrote:
               | the bigger problem is we have lost the true meaning of
               | "science" or rather the "scientific method" as a huge
               | part of forensic "science" has no connection with the
               | "scientific method" upto and including the foundational
               | "science" of fingerprints which is more of interpretive
               | art than science
               | 
               | Too much of science today is Hypothesis -> Gather Data to
               | support, reject any that does not -> Report Conclusions
               | -> Burn Heretics
        
         | levi_n wrote:
         | "2biteencryption", name checks out
        
         | Jenda_ wrote:
         | > But the humans who testify on the dogs' behalf have a cult-
         | like behavior about what the dogs can realistically detect, and
         | how they interpret the dogs behaviors.
         | 
         | There was a scandal here in .cz regarding forensic odorology
         | using dogs, as a report came out where the authors basically
         | found out they were unable to test it, because the dog-
         | operators either did not understand what is a double-blind
         | experiment, or they even actively sabotaged it. It is then
         | implied that when they do the identification for real, they are
         | not blind to who the suspect/control is. (report, unfortunately
         | only in Czech: https://jenda.hrach.eu/f2/salamoun-testovani-
         | pachovych-stop.... google translate:
         | https://jenda.hrach.eu/f2/salamoun-testovani-pachovych-stop-...
         | )
        
           | rnk wrote:
           | It's clear that this resistance to being reasonably tested is
           | because the handlers are obviously influencing the dogs. It's
           | freaking irritating. A lot of that is drug war bs. I thought
           | only us law enforcement would be resistant to evaluation.
        
       | cybervegan wrote:
       | This little eggcorn in the article made me chuckle "little to
       | know" (should be "little to no").
        
       | Jenda_ wrote:
       | https://en.wikipedia.org/wiki/Annie_Dookhan
       | 
       | I find it shocking that there is no "continuous quality
       | assurance" of these labs - for example, one should take the lab
       | as a blackbox, and send 10% known-negatives, 10% known-positives,
       | and 10% random samples from previous batches in every batch, and
       | then evaluate a) how many known positives/negatives turned out
       | right, b) how many samples from previous batches return the same
       | result.
        
       | vanattab wrote:
       | How offen are people bitting people and only being id through the
       | bite marks? Are there people sneaking into bedrooms biting
       | people? I don't get it.
        
         | rossdavidh wrote:
         | Typically it's a "man bites dog" kind of case. [ducks]
        
         | mypalmike wrote:
         | When there are violent struggles, it's not actually that
         | uncommon for bite marks to be present on victim or assistant.
         | 
         | *Source - I've seen lots of episodes of Forensic Files.
        
         | OkayPhysicist wrote:
         | I'd imagine it's not uncommon for bite marks to be at least one
         | piece of evidence. Victim struggles, bites assailant, cops
         | arrest somebody with a bite mark, suspect insists it's from
         | some fun times with their SO and not from a victim defending
         | themselves, cops call upon their pseudoscientists to "prove"
         | that the bite mark came from the victim. Or another way around,
         | a victim of a violent assault might have been bit while
         | fighting off their attacker. In a grappling scenario, there is
         | definitely a portion of the population who will instinctively
         | use their teeth, from my experience in water polo, I'd reckon
         | about a quarter of people.
        
         | beastie29a wrote:
         | There was an HBO documentary series named Autopsy[0] I watched
         | back in the 90s and two crimes stick out. The series mainly
         | followed the case file of a Forensic Pathologist named Dr.
         | Michael Baden.
         | 
         | If I can remember them correctly, one case was a murder that
         | appeared as a break-in and a bite marking found on a garbage
         | bag was tied back to the victim. The other was an inmate that
         | left bite marks on a guard and tied the crime back to the
         | inmate with.
         | 
         | It's so interesting to see this research now and wonder what
         | would come of those cases now that the main evidence is
         | seemingly unreliable.
         | 
         | [0] https://www.hbo.com/autopsy
        
       | kuprel wrote:
       | Bite marks were used to convict Ted Bundy
        
       | luxuryballs wrote:
       | I'm surprised that this even needed a study, which also makes it
       | rather alarming.
        
       | holiveros wrote:
       | Mexican here, in my country these type of "evidences" are harder
       | to support / enforce, as long as your lawyer / you are willing to
       | provide enough scientific indication they're not reliable, those
       | evidences are dismissed.
       | 
       | Of course, as any country, there's corruption at every level.
       | 
       | Wonder what's the stance of other countries?
        
         | bombcar wrote:
         | Often these types of evidences are used to get the subject to
         | confess or agree to a plea deal.
         | 
         | (In other words, they're often used "when we know you did it"
         | kind of things.)
         | 
         | The justice industry isn't very pretty, best not to look too
         | closely at it.
        
       | Zigurd wrote:
       | "Crime labs" cannot be trusted. They are unaccountable and
       | dependent on police departments for funding. Their results are
       | "good" if people get convicted. That's perverse and contrary to
       | scientific principles. That extends to publications in that
       | field. It's systemically corrupted and needs to be restructured
       | to be independent of police and prosecutors.
        
       | irsagent wrote:
       | Are any implications drawn from these findings from a dentist
       | perspective?
        
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