A teenager has been stabbed to death in east London.
Officers were called to Homerton High Street at about midnight but the boy, believed to have been in his mid-teens, was pronounced dead at the scene.
Police said it was believed the victim had been involved in an altercation with three or four youths when leaving a shop on the high street.
The Metropolitan Police said the death was being treated as murder but no-one had been arrested.
It said the Directorate of Professional Standards was reviewing "police contact with the victim" earlier in the evening and the matter had been referred to the Independent Police Complaints Commission.
Det Ch Insp Ken Hughes said: "It would appear the victim was chased by the group to Ponsford Street, where he was stabbed. The suspects then ran off in an unknown direction."
BBC London 94.9 reporter Colleen Harris, who was at the scene earlier, said: "People on their way to work and to school were being diverted away while forensic experts gathered evidence from the scene of last night's killing.
"This is a really busy junction and police will be wanting to speak to anyone who has seen or heard anything."
Ponsford Street has since reopened.
Scotland Yard said the teenager had become the seventh person to be killed in London in the first week of 2015.