Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. US Capitol Riot Prompts Fresh Focus on Extremism in US Police Ranks Masood Farivar WASHINGTON - The January 6 deadly riot at the U.S. Capitol has renewed attention to what has long been an open secret in police departments across the country -- right wing extremists populating their ranks. For years, even as experts warned about the growing dangers of extremism in police departments, many police chiefs brushed the concern aside as a social media nuisance. Now, in the wake of revelations that dozens of current and former law enforcement officers, firefighters and military personnel may have taken part in the January 6 riot, police leaders are being forced to own up to the problem. Five people died in the assault, including a Capitol Police officer, Brian Sicknick, who was struck in the head with a fire extinguisher thrown by a rioter, while many other police officers were injured. Former President Donald Trump is facing an impeachment trial in the Senate on charges of inciting an insurrection of his supporters at the Capitol to prevent the certification of President Joe Biden's election. At least 30 police officers from more than a dozen states, ranging from Virginia and Pennsylvania to Oklahoma and California, are being investigated by their superiors for their conduct in Washington, or face criminal charges for taking part in the rioting at the Capitol. "The biggest fault of law enforcement has been viewing the extremism language of fellow law enforcement officers and viewing it as freedom of speech instead of seeing that that language, those comments, actually chisel away at the democracy of America," said David Mahoney, the sheriff in Dane County, Wisconsin, who is president of the National Sheriffs' Association. Last Tuesday, as federal agents moved to charge a Houston Police Department officer in connection with the Capitol rioting, Chief Art Acevedo delivered a blunt warning to a group of cadets. "If anyone in this room right now believes that anyone needed to be in the Capitol building, you need to check out," Acevedo said. "You will not survive in this department with that mindset." Involvement in US Capitol riot The same day, Tam Pham, an 18-year veteran of the Houston Police force, was charged with two counts of illegally entering the Capitol building and engaging in disruptive conduct. Pham initially told federal agents that he and his wife had traveled to Washington on business and while he attended a Trump rally on the morning of January 6 near the White House, he did not enter the Capitol. But his story changed after agents searching his cell phone found selfies of him inside the building. One showed Pham standing next to a statute of President Gerald Ford draped in a Trump flag as rioters roamed through the building. .