He has now been named as 60-year-old Krasimir Kartikov, originally from Bulgaria.
A special post-mortem examination carried out on Wednesday, 15 January gave the cause of death as multiple injuries.
His next-of-kin have been informed.
Detective Chief Inspector Helen Rance, who is leading the investigation, said: “Our investigation is moving quickly but we are keen to speak to anyone who saw or spoke to Krasimir after 4pms on the afternoon of Saturday, 11 January.
“We would also ask anyone who may have been in the Whitehorse Road area to think back as to whether they heard any kind of disturbance or saw anything unusual that Saturday evening and overnight into Sunday.
“Krasimir’s family are understandably devastated at the death of their loved one and we are committed to finding out exactly what happened that night and bringing the person/s responsible to justice.”
Anyone with information should call the incident room number on 020 8721 4266