A 14-year-old boy stabbed a man to death in a dispute over a bike.
The defendant, who cannot be named, had denied murdering 39-year-old Darren Edginton in the St Pauls area of Bristol on 21 June.
He was convicted of manslaughter at Bristol Crown Court and will be sentenced on 3 February.
Avon and Somerset Police said he was "one of the youngest people" to be convicted of the charge in the force's area.
The court previously heard the victim, the defendant and most of his friends had been on bicycles when witnesses heard Mr Edginton shout about a stolen bike.
The jury was told the teenager and Mr Edginton went to a secluded lane following a dispute about the bike, which the victim was riding but that the teenager and his friends felt was theirs.
'Still a child'
A witness told the court he had heard Mr Edginton say he had been stabbed shortly before he collapsed. He died in hospital from a single stab wound.
Ch Insp Paul Wigginton, from the force, said police were "aware of [the boy's] history of vulnerability and criminal exploitation" and his background would "undoubtedly" have been a contributing factor, but it "doesn't excuse the horrific crime he's committed".
He added: "The fact a teenage boy has been found guilty of manslaughter is extremely sad and while he's got to take responsibility for his own actions, he's still a child and something has clearly gone wrong for him to be in the position he now finds himself in."