ITS ORIGIN AND PURPOSE, STILL A TOTAL MYSTERY: London Bridge knife attacker known to cops, wore electronic tag, had links to jihad terror groups. “The attacker was a convicted terrorist who had recently been released from prison and was wearing an electronic tag, according to The Times. The report added that he was a guest at a Cambridge University conference on prisoner rehabilitation at Fishmongers’ Hall – where the attack began – and later threatened to blow up the venue.”