The killer of headmaster Philip Lawrence has been bailed by detectives investigating a street mugging.
Learco Chindamo, 30, was arrested on suspicion of mugging a young man after he used a cash machine in Camden, north London.
Detectives said they suspect a gang of people may have been threatening people who used the machine in the early hours.
A Metropolitan Police spokesman said three men and a woman were suspected of mugging the victim, aged in his twenties, near a branch of Sainsbury's in Belmont Street at the junction with Chalk Farm Road on Saturday November 13 at 3.40am.
Chindamo, who walked free from jail in July, 15 years after knifing the teacher to death in Maida Vale, west London, has been recalled to prison on licence.
Father-of-four Mr Lawrence, 48, was knifed and fatally wounded after going to help a pupil who was being attacked by a gang.
Among the attackers was Chindamo, then 15, who went on to brag about the killing hours later. He was convicted of the murder in October 1996, jailed indefinitely and ordered to serve a minimum of 12 years.
The headmaster's widow, Frances Lawrence, has complained that the authorities did not tell her where Chindamo was living and that his rights seemed to be put above hers.
The Prime Minister's spokesman said David Cameron was "very concerned" about Mrs Lawrence's distress over his recall to prison. but he said the law gave the Ministry of Justice no choice but to withhold details of Chindamo's address.
He said: "It is not a question of giving more rights to criminals than to victims. It is an issue about compliance with the law. Providing further information would very likely have been unlawful and clearly the department can't do something that breaks the law."