The man who knifed two people to death on London Bridge before being fatally shot by police Friday was a convicted terrorist released from custody a year ago after agreeing to wear a tracking device, according to the Metropolitan Police Department. Police identified the man as 28-year-old Usman Khan, who was convicted of terrorism-related offenses in 2012. He was attending a Cambridge University conference on prison rehabilitation on Friday when he threatened to blow up the hall and then went on a stabbing rampage, The Times of London reported.