A 15-year-old boy has been found guilty of fatally stabbing a friend after trading insults on Facebook.
The teenager stabbed 18-year-old Salum Kombo in the chest after being called names including "pussy".
Mr Kombo bled to death near the scene of the attack in Bromley-by-Bow, east London, in December 2009.
The defendant, now 16, who cannot be named, has been held in custody before sentencing in July.
Det Insp Joe Daly said outside court: "The tragic events which unfolded that night were the culmination of a combination of factors - a trivial argument, the defendant's over-sensitivity about his own dignity and status, and his willingness to carry a knife.
"As a result an 18-year-old has needlessly lost his life and a 16-year-old is now set to spend his young life behind bars."
The jury was told he was arrested on the day of the attack and said he was acting in self-defence.
David Jeremy QC, prosecuting, said it was a case in which "a young man has lost his life by being stabbed following a petty dispute and a perceived loss of face by the perpetrator".
"That was the pathetic reason as to why this terrible event happened," said Mr Jeremy.
He said that a friendship between Mr Kombo and the defendant had turned to "hostility" and they had a fight last summer after a football match.
The court heard that on the evening of 20 December the defendant met friends outside a fish bar and was "angry" and talked about stabbing Mr Kombo.
When Mr Kombo turned up, they exchanged words and walked off, apparently either to talk through their differences or settle them in a fight, jurors were told.
As they did so the defendant "without any warning" pulled out a knife from his pocket and stabbed Mr Kombo to the upper chest, Mr Jeremy said.