Three people have been found guilty of murdering a teenager, who was beaten to death in a gang attack in January 2006.
Mr Osman suffered three fatal stab wounds during the attack
A film of Mahir Osman being attacked by up to 40 people in Camden, north London was shown to the Old Bailey jury.
The CCTV images showed Mr Osman being punched, stamped on and stabbed 20 times near Camden Tube station.
Ismail Mohamed, 20, Liban Elmi, 20, and a 17-year-old boy who cannot be named for legal reasons, will be sentenced on 11 May.
The jury at the Old Bailey heard that the attack was the result of a feud between rival Somali gangs.
The gangs were from the Camden and Tottenham-Edmonton areas of London.
The jury was shown footage of the mob carrying wooden bats, bottles, hammers and knives.
"It is all over literally in seconds," Brendan Finucane, QC, prosecuting, had said during the trial.
"He was set upon by a gang of up to 40 Somali youths. It lasted less than a minute."
After the attack, they tried to get away on a bus before it was stopped by police, the court was told.
Some of the gang evaded arrest by climbing out of the emergency exit at the back of the bus.
A man, aged 25, who cannot be identified for legal reasons, was found guilty of conspiracy to wound and violent disorder.
Mohamed Mohamud, 18, Abdirahman Mohamed, 18, and youths, aged 16 and 17, who cannot be named for legal reasons, were found guilty of violent disorder, conspiracy to wound and conspiracy to have weapons.
Det Ch Insp Michael Broster said: "This group of men went to Camden with the sole intention of attacking anyone belonging to the opposing group.
"It was a premeditated attack using a level of violence I have rarely seen."