A 14-year-old girl is to appear in court on Monday charged with the murder of a promising teenage footballer described as a "role model" for his community.
The girl, who cannot be named for legal reasons, will appear at Camberwell Green Youth Court, a spokesman for the Metropolitan Police said.
Police are also questioning a 16-year-old boy at a south London police station after he was arrested on suspicion of murder on Saturday.
Junior Nkwelle, 15, was stabbed to death outside a block of flats on the Loughborough Estate in Brixton, south London, on Thursday evening.
He was pronounced dead at the scene, with police saying the killing was not believed to be gang-related.
Junior's mother, who wished to be known only as Stella, issued a short statement through the police last night pleading for anyone with information to tell officers.
She said: "I would like all of the kids who saw what happened to my son to come forward and speak to the police.
"I am pleading with the parents to let their children do that, and to support their children in telling the truth. If they do not it could lead to this happening again one day."