A 14-year-old girl has been found guilty of arranging the killing of a "kind, ambitious and humble" schoolboy after a row over football.
Junior Nkwelle, 15, was knifed in the heart and lung on a housing estate in Brixton, south London, last September.
The Old Bailey found the girl and her boyfriend, 17, guilty of manslaughter but not guilty of murder.
The pair, who cannot be identified for legal reasons, will be sentenced on 5 April.
Jurors heard Junior and his friends had been playing football on the Loughborough estate when an argument broke out.
The girl and her friends appeared to have taken offence over some matter, jurors were told.
The court heard Junior was subsequently stabbed in the chest after his killer arrived on a bus.
'Teach him a lesson'
Jonathan Turner, QC, prosecuting, said it was likely the pair did not know each other and there was no previous quarrel between them.
He said: "He [the defendant] had been telephoned by his girlfriend and told to come to the estate to teach Junior Nkwelle a lesson.
"She thought that Junior had insulted her or been less than respectful to her.
"She was very angry and determined that he should be punished - indeed stabbed - to put things right."
Following the conviction, Junior's mother Stella issued a statement which said: "Junior was my first child.
"I cannot actually believe he has been taken from us and still at times I expect him to walk through the front door.
"Even five months on I feel in a daze, like this is a bad dream, and one day I will wake up and he will be there at home laughing and talking about football.
"Then I am hit by the sad reality and the pain is indescribable.
"I had no chance to help, or see him and say goodbye and tell him how much I love him because by the time I got to him my poor child had bled to death.
"I wake every day and see where my boy was killed, the vision of him lying on the floor wounded, breathless, motionless - a horrific vision that is engraved in my mind.
"At night when I try to sleep that horrific night revisits me."
Det Ch Insp Charles King, of the Homicide and Serious Crime Command, said: "The death of Junior Nkwelle illustrates the terrible consequences of what appears to be the casual acceptance that knives have a part to play in minor disputes between young people.
"I hope that these convictions today go some way in helping Junior's family move forward."