A man found dead in north-west London was killed in a drive-by shooting, police said.
The 24-year-old man was found with a gunshot wound in Malden Road, Kentish Town, late on Sunday.
CCTV revealed two people on a moped had pulled up to the victim, pulled out a gun and fired at close range. The man died at the scene.
An eyewitness described how he tried to perform CPR on the man with the help of a 999 operator.
Will, who did not want to give his full name, said: "There were a number of people around him when I got down there, but nobody was doing anything.
"With the aid of the operator on the phone, I performed CPR. But I think he was already dead then."
Officers said they were keen to trace people who had been in a Toyota Prius, a Ford Focus and a motorbike in the area at the time.
The man's next of kin have been informed and post-mortem tests are due to be held on Tuesday, police said.
Det Ch Insp Simon Stancombe, from the Met Police, said: "Everything we have found out so far points to this being a drive-by shooting."
He urged eyewitnesses or anyone with dashcam footage to contact the force.
The killing was the second fatal shooting in less than 12 hours in London.
A man in his 20s was shot dead in Sydenham, south-east London, on Sunday afternoon.