A 15-year-old boy is due to be sentenced later for murdering a teenager outside the gates of his school in front of horrified students.
Quamari Serunkuma-Barnes, also 15, was chased and stabbed three times outside Capital City Academy in Willesden, west London, by a masked attacker in January.
The attack in Doyle Gardens came shortly before 3.30pm on January 23, as children left the school, which specialises in sports and the arts.
Quamari, who was preparing to sit his GCSEs this summer, died in hospital later the same day after undergoing surgery.
The killer, who cannot be identified for legal reasons, was found guilty of murder following a trial at the Old Bailey last month.
Despite the mask, witnesses had recognised him and he was arrested the day after the attack.
After the verdict, Detective Chief Inspector Jamie Stevenson said many of the children who saw the attack initially assumed the boys were "messing around".
He said: "Little did they know that within a matter of minutes Quamari would be lying helplessly on the ground fighting for his life.
"Those that witnessed the events have been left completely devastated by the loss of their friend."
He added: "This was a deliberate and planned attack on a defenceless schoolboy as he made his way home laughing and joking with friends.
"Quamari didn't stand a chance that day. He was outrun by his attacker who had an advantage over his victim in that he was an adept runner and was able to quickly catch up with Quamari."
The killer is due to be sentenced at the Old Bailey.