A teenage boy has been shot dead in a street in south London.
Detectives say there were many witnesses to the murder
The victim, believed to be aged about 18, was found on Friday at 2210 BST on Marcus Garvey Way, near Brixton underground station.
He was taken to hospital, where he was later pronounced dead. The teenager has not been formally identified.
Forensic tests are being carried out at the scene of the shooting. The killing takes the number of teenagers murdered in London this year to 17.
It is believed the victim was part of a group of 10 or 11 youths who had gathered in Marcus Garvey Way.
They were approached by a black man on a blue motorcycle or scooter who was wearing a helmet.
He began talking to them before revealing a gun and shooting it towards the group.
Police said they had been talking to the many witnesses to the attack.
Det Ch Insp Adnan Qureshi said: "I would appeal to anyone who may have been in the vicinity of Marcus Garvey Way last night, or indeed members of the group who were with the victim at the time, to come forward.
"It may be that people who weren't present have subsequently been told what happened, and it is vital that they share this information with us."
Police confirmed that no-one else was injured in the shooting.
Last week, 16-year-old Abukar Mahamud was killed by a single bullet wound to the neck after apparently being chased by a gang of youths on bicycles.
He was gunned down in the Stockwell Gardens Estate in Stockwell, south London, in the early hours of 26 July.
Other murders of teenagers this year have included the stabbing of Adam Regis, the 15-year-old nephew of Olympic sprinter John Regis, and the shooting of 15-year-old Michael Dosunmu, a regular churchgoer, which police believe was a case of mistaken identity.