Four men, all Tamils, have been found guilty at the Old Bailey of attacking a teenager and beating him to death before setting fire to his body.
The victim's body was found blistered by fire
The body of Supenthar Tamachandran, 18, from Wembley, north London, was found in February last year in Roe Park, Kingsbury.
Senthamil Thillainathan, 21, Pradeep Sivanesan, 18 and 30-year-old Kannan Sivakumar, all from Wembley, and a 17-year-old who cannot be named had all denied murder.
They will be sentenced on Monday.
The court heard that the dead man had been repeatedly picked on by other Sri Lankans while they were eating at a Tamil restaurant in Wembley.
He was taken off in a car against his will and attacked by the gang in the park.
Aftab Jafferjee, prosecuting, told the jury not to look for any logic in the motive but accept it was "sheer cruelty".
Thillainathan was also found guilty of the axe murder of a 25-year-old man a year before in a revenge attack.
Arvinthan Muthukumarasamy was repeatedly struck on the head with an axe as he sat with four others in a car in Wembley.
Thillainathan's accomplice, Sivivageethan Punniyamoorthy, 22, was convicted of the murder at an earlier trial.
The jury was unable to agree a verdict in Thillainathan's case and he was retried alongside the park murder case.
The case was one of the longest at the Old Bailey and began last November.