A teenage boy who was stabbed to death in north London has been named by police as 15-year-old Romario Opia.
Officers were called to Holland Walk in Islington at about 5.30pm on Monday.
Romario was pronounced dead at the scene a short time later, Scotland Yard said.
Homicide detectives from the Met's specialist crime command have begun a murder inquiry, with local residents being told to expect an increased police presence in the coming days.
While formal identification is yet to take place, officers believe the victim is Romario, and his next of kin have been informed.
A boy aged 16, who was arrested on suspicion of affray, has been released with no further action.
Chief Superintendent Raj Kohli, commander of the Central North unit, said he knew the community would be "shocked and upset by this incident", adding that "detectives will be making extensive inquiries".
Detective Chief Inspector Neil John, who is leading the investigation, urged people with mobile phone footage to share it with officers.
"There are people out there who know what happened last night, and I want them to come forward," he said.
Anyone with information is asked to call 101 or tweet the Met Contact Centre (@MetCC).