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. Terror Attack Has Britons Questioning De-Radicalization Effort Jamie Dettmer LONDON - When Usman Khan left prison last December after serving half of a 16-year sentence for his part in a plot to blow up the London Stock Exchange, and for planning to establish a terror training camp in Pakistan, he was thought to be making good progress towards being de-radicalized and was seen as a poster boy for Britain's rehabilitation programs. Cambridge University, which ran one of the programs Khan attended, was even considering offering him a place to study. But now following 28-year-old's dramatic knife attack Friday on London Bridge during a university-sponsored justice event, which left two people dead and three seriously injured, the early release of convicted terrorists, as well as de-radicalization programs, are coming under immediate scrutiny amid accusations that militants are gaming the rehabilitation system and hoodwinking authorities. Some criminal justice experts say Khan played the rehabilitation system cleverly to secure his release and to lull his probation officers into allowing him to travel unsupervised from his home in the English county of Staffordshire to London for the justice event, where he killed two rehabilitation tutors, 25-year-old Jack Merritt and 23-year-old Saskia Jones. "Despite the monitoring he was subjected to, he was able to convince everyone he was well on the way to being a reformed character," according to Harry Fletcher, a criminal justice expert and campaigner for victims' rights. Khan's attack wasn't opportunistic, but deliberately planned, say British counter-terror officials. With fears mounting that other recently freed terrorists may also be playing the system, a crackdown has been launched that's likely to see a large number of them returned to prison. One of Khan's close associates, 34-year-old Nazam Hussain, who was freed from jail the same day as the London Bridge killer, was re-arrested Sunday on suspicion of preparing terrorist acts. At least 74 freed terrorists are being vetted again, according to British Prime Minister Boris Johnson, who said in a broadcast interview Sunday that they all needed to be "properly invigilated so as to make sure there is no threat to the public." .