Police have released an image of a murder victim as they continue to appeal to members of the Somali community in Streatham who may have information about the attack.
People in the vicinity when Hanad Osman, 24, was stabbed in the neck are also asked to come forward to speak with detectives.
Despite the efforts of emergency services Mr Osman was pronounced dead at 8.20pm on Tuesday after police found him at the rear of Waaberi Business Centre in Gleneldon Mews.
Detective Chief Inspector Charles King said: "He was the victim of a brutal assault and I would urge anyone with any information that may assist my officers to come forward.
"I can assure you that you will be treated with the utmost discretion."
Anybody with information should call police on 020 8721 4054 or Crimestoppers anonymously on 0800 555 111.