A week on from the apparently motiveless murder of a "gentle giant" in New Cross, detectives will be returning to the scene tonight in the hunt for potential witnesses.
Andrew Oteng-Owusu, 19, was found by his mother - who he cared for - dying on his own doorstep in Sharratt Street SE15.
Andrew Oteng-Owusu
Andrew Oteng-Owusu
No arrests have been made so far and officers will be visiting the area tonight, to hand out appeal leaflets in the hope someone with information comes forward.
Detective Inspector Mick Norman, leading the investigation, said: "The local community on the Lovelinch Estate have been really supportive but so far we really don't know why Andrew was stabbed to death that night.
"He has been described as a "gentle giant" and he was a carer for his mother who is on dialysis. Andrew had not been in trouble with the police before and there are few clues as to why this might have happened.
"What we do know is that he was stabbed on the other side of the estate, at the junctions of Hornshay Street and Lovelinch Close. He then staggered home where he banged on the front door before collapsing.
"We are appealing for any witnesses or anyone with any information, no matter how small, to please come forward and help us solve Andrew's murder.
"In particular we are very keen to trace a young black man who, after the stabbing, walked with Andrew to the block of flats where he lived. He is aged in his late teens or early to mid-20s and was wearing a white T-shirt. If you can help, please approach us in confidence."
Andrew's mother Tina Ababio has also made an emotional appeal for help.
She said: "Andrew was a very gentle, humble and polite young man, helpful to everyone he knew, especially in the neighbourhood.
"He was a wonderful carer for me and my only child and loved by everyone who knew him because of his nature.
"I don't understand who would be capable of taking his life."
A murder investigation was launched after Andrew was fatally stabbed on the night of Wednesday, 3 August.
Police were called by the London Ambulance Service (LAS) at 23:41hrs to Sharratt Street, SE15 and found Andrew seriously injured.
He was taken to King's College Hospital where he died at about 11:30hrs on Thursday, 4 August.
A post-mortem examination held at Greenwich Mortuary the following day gave cause of death as a single stab wound.
Police previously appealed to find a man riding a moped who helped direct officers to Andrew on the night. He has now been traced.
Anyone with information is asked to contact the incident room at Lewisham police station on 020 8721 4961. To remain anonymous call Crimestoppers on 0800 555 111.