A promising footballer, 15 year-old Junior Nkwelle, has been stabbed to death outside a block of flats in Brixton.
Officers were called to reports of a disturbance on the Loughborough Estate just before 9.25pm on Thursday and found the boy with serious stab wounds.
He was pronounced dead at the scene.
Locals were shocked by the death as they gathered to inspect floral tributes placed outside Secker House in Minet Road.
One card on a tribute said: "Dear Junior, You was a good friend, a great footballer and a great person. Justice will happen. I promise!"
Another said: "If football be the food of love 'Play on'. RIP young fella."
Solomon Smith, 27, a youth support worker at Marcus Lipton Youth Centre a few yards from the scene, said yesterday: "He was one of our locals, and had been coming here for about two years.
"He was a very good footballer. When he came in, he always played football indoors here.
"He was a very quiet guy, you wouldn't think anything like this would happen to him.
"Because it's Brixton, and there's blocks of flats, you get gang troubles round here. There's been gang wars with guys from Stockwell and Tulse Hill, and that's what we are trying to tackle."
A Metropolitan Police spokesman said the dead boy was from the Loughborough Estate and that his next of kin had been informed.
A post-mortem examination was being carried out last night at Greenwich mortuary and Lambeth-based detectives, together with officers from the homicide and serious crime command, are investigating.
Anyone who could assist the inquiry was urged to call detectives on 020 8721 4054 or Crimestoppers anonymously on 0800 555 111.