A knife attacker who killed two people and injured several others Friday on London Bridge was sentenced to 16 years on terrorism charges in 2012 and released in 2018, according to officials.
The suspect, 28-year-old Usman Khan, wore a fake suicide vest during the attack before he was tackled by several bystanders and shot dead by London police responding to reports of "a stabbing at premises near to London Bridge" around 2 p.m., officials said.
U.K. counterterrorism police are now investigating the situation. Khan had been convicted as part of a group that denied plotting to target major sites including Parliament, the U.S. Embassy and several prominent individuals, including two rabbis.
Khan admitted to engaging in conduct for the preparation of acts of terrorism. He had been secretly taped plotting attacks and talking about martyrdom as a possibility.
Neil Basu, London’s police counterterrorism chief, said Khan was attending a program that works to educate prisoners when he launched Friday’s attack just yards from the site of a deadly 2017 van and knife rampage.
The attack raises difficult questions for Britain’s government and security services. Police said Khan was convicted in 2012 of terrorism offenses and released in December 2018 "on license" which means he had to meet certain conditions or face recall to prison.
Several British media outlets reported that he was wearing an electronic ankle bracelet at the time of the attack.
Chris Phillips, former head of Britain’s National Counter Terrorism Security Office, took issue with asking law enforcement to keep the country safe while letting people out of prison when they are still a threat.
"We’re playing Russian roulette with people’s lives, letting convicted, known, radicalized jihadi criminals walk about our streets," he said.
Prime Minister Boris Johnson, who visited the scene Saturday, said he had "long argued" that it was a "mistake to allow serious and violent criminals to come out of prison early," adding that additional security measures have been taken on nearby streets to reassure locals.
President Donald Trump is expected to visit London this week for NATO talks.
The Associated Press contributed to this report.