Police are searching for an armed motorcyclist who opened fire on a group of young people, killing a teenager.
The victim, who is believed to be 18 or 19, was found with gunshot wounds by police on Friday night in Brixton, south London.
His death brings the number of teenagers murdered in London to 17 this year.
Police found the man, who has not been formally identified, in Marcus Garvey Way, near Brixton Underground station, after they were called to reports of shots being fired. He was taken to hospital but later died.
It is thought the youngster was part of a group of between 10 and 11 youths aged about 17 or 18, who were gathered in the small residential cul-de-sac when they were approached by another teenager on a motorbike.
The suspect, who is believed to be about 18 and was on a blue motorcycle or scooter and wearing a helmet, spoke to members of the group before producing a gun and firing towards them.
Chief Inspector Adnan Qureshi said the rider spoke to the youths before there was "an altercation of some description" and a series of shots were fired.
He confirmed that the victim was a black 18 or 19-year-old man from the local vicinity.
Police are keeping an open mind as to the subject of the disagreement and say that they are not entirely clear about the motive at the moment. A post-mortem examination will take place today. There have been no arrests.
:: Anyone with information is asked to contact the incident room on 020 8247 4554 or to remain anonymous call Crimestoppers on 0800 555 111.
