Ernest Kalawa, 24, was stabbed to death in Peckham on 30 December 2016.
Police and paramedics were called to an area outside Deerhurst House in Haymerle Road at around 5.30pm.
Mr Kalawa, who was also known as Alex and lived in Southwark, was pronounced dead at the scene and a post-mortem gave cause of death as multiple stab wounds.
A 23 year-old man was arrested on suspicion of murder on 31 December and released on bail.
Detective Chief Inspector Lee Watling of the Homicide and Major Crime Command appealed for witnesses and information.
He said: "Did you see anything suspicious around 17:30hrs last Friday afternoon near Haymerle Road or Frensham Street, Peckham?
"I am extremely keen to hear from anyone who was in the area of this tragic incident as they may hold vital information that will assist our investigation. I would urge anyone who witnessed the assault or the moments leading up to it to call police and tell us what they know."
Ernest's family said in a statement: "Ernest's tragic death is a massive loss to the family. Everyone is in shock and struggling to come to terms with the loss of our son, brother, cousin, and friend. At the moment the pain is still very fresh.
"Our family only really want time and space to grieve in private, and ask that the press and media respect our wishes. Ernest was loved and cherished and we all miss him deeply."
Anyone who witnessed the assault, or moments leading up to it, is asked to contact the incident room on 020 8721 4205 or via 101. To give information anonymously contact Crimestoppers on 0800 555 111 or visit crimestoppers-uk.org.