A 15-year-old boy has been arrested on suspicion of murdering another 15-year-old near a London shopping centre.
Baptista Adjei, from North Woolwich, was found critically injured on Stratford Broadway, east London, shortly after 15:20 BST on Thursday.
Police believe he and a 15-year-old friend were either attacked on a bus, or shortly after getting off.
Another boy was arrested on suspicion of murder after handing himself in on Friday evening.
The Met Police said he had been remanded in custody.
Det Ch Insp Chris Soole said the two boys were stabbed during a fight "on or shortly after alighting from a bus which stopped very close to Stratford Shopping Centre, near tramway Avenue".
The shopping centre is adjacent to Stratford Westfield.
"The victim of this stabbing was a schoolboy with his whole life ahead of him. He had everything to live for.
"This was a senseless attack and we share the concern and alarm this murder will no doubt cause in the local community," he said.
The second injured boy was taken to hospital with non-life threatening injuries.
Baptista's friends and members of the public provided first aid but he died at the scene at about 15:50, police said.
A Section 60 order was implemented, giving officers increased stop and search powers across Newham.
Police closed off a large part of Broadway, and the shopping centre entrance nearest Stratford Station was closed.
In a separate stabbing about five hours later, an 18-year-old man was knifed to death in south London.
Police found the man suffering from stab injuries on the Brandon Estate in Camberwell, at about 20:20.
He died an hour later. No arrests have been made.
A 15-year-old boy has been arrested on suspicion of murder after handing himself in at an east London police station today.
— Metropolitan Police (@metpoliceuk) October 11, 2019