The homeless man beaten to death at Partnership House, a derelict office block in Waterloo Road, has been named as Tomasz Bundyra, 28, of no fixed abode.
A post mortem gave cause of death as multiple blows to the head, torso and legs.
Anyone who can assist should call the incident room on 020 8721 4155; if you wish to remain anonymous call Crimestoppers on 0800 555 111.
Five men appeared at Camberwell Green Magistrates Court on Saturday charged with Bundyra's murder. They were remanded in custody to appear at the Old Bailey in May.
A sixth man appears at Camberwell Green Magistrates Court on Monday, also charged with murder.