Kodjo Yenga was stabbed in the heart
Five teenagers have been found guilty of killing 16-year-old schoolboy Kodjo Yenga.
The gang, armed with knives, bats and a bull terrier, screamed "kill him" as they ambushed Kodjo last March.
One said he was in a confrontation with Kodjo in Hammersmith, west London, and did not expect others to join in.
Two youths, aged 14 and 17, were found guilty of murder and three others, aged 17, 14 and 15, were found guilty of manslaughter at the Old Bailey.
None of the defendants or young witnesses can be named because of their ages.
Objected to bail
After the verdicts, it emerged that the 17-year-old found guilty of manslaughter was in court just hours before Kodjo's death.
Despite objections from the police he had been given bail by magistrates after being arrested for the theft of a bicycle and for intimidating a witness.
He was part of a gang that attacked Kodjo that afternoon.
Prosecutor Sir Allan Green QC said a woman saw a group of about 10 youths chasing Kodjo, who was running away.
"She could hear a few members of the group shouting 'catch him, kill him'," he told the court.
The schoolboy was stabbed in the heart and collapsed in the street, where his 15-year-old girlfriend found him.
She said: "I put his head in my lap and I was crying and I said 'Please don't die, please don't die'."
She said she had pleaded with Kodjo not to go into the area after he was challenged to a fight by one youth.
He had said: "I'm not scared of anyone. If you want to fight, let's do this."
The attackers were young members of the MDP, Murder Dem Pussies or Money, Drugs, Power, a local gang.
A trademark of the MDP is to attack boys by suggesting a one-to-one fight outside their local area, culminating in a "serious assault with various weapons", according to the prosecution.
Outside court, Kodjo's mother, Ladjua Lesele, said: "These cold-blooded children tormented and stabbed my wonderful and innocent son whilst they screamed 'kill him, kill him' during his calculated murder that was premeditated and planned.
"I only have one thing to say to those who murdered Kodjo - as you spilled and touched his blood, no matter how many times you wash your hands, his blood will stay on them for as long as you live."
A sixth youth was cleared of all charges. The guilty teenagers will be sentenced on 9 May.