Detectives investigating the murder of David Idowu on the Tabard Gardens Estate believe there are witnesses who have yet to come forward.
David was stabbed four weeks ago at 5pm in the area around Tabard Street and Great Dover Street. Despite being taken by air ambulance to hospital and a further three weeks of treatment, he died on Monday 7 July.
A post mortem gave cause of death as multiple organ failure and a stab wound to the heart.
Since his death the investigation has passed to detectives from the Homicide and Serious Crime Command (HSCC), and they are using the four-weeks-on 'anniversary' to appeal for those with information to come forward.
"From our review of the investigation to date we know that there are other witnesses to David's murder who have yet to help the investigation," says Detective Inspector Graeme Gwyn.
"David's family have been devastated by his death and it is imperative that we achieve justice for them.
"David fought bravely for three weeks to overcome his injuries. I would ask those who have yet to tell us what they saw or know, to show bravery themselves and step forward to help us take a killer off the streets."