Darcy Austin-Bruce died from multiple gunshot wounds to the torso
A fourth man has been arrested in connection with a fatal shooting outside Wandsworth Prison.
Darcy Austin-Bruce, 20, was shot on Heathfield Road outside the jail in south-west London on Friday afternoon. It is thought he was a prison visitor.
A 27-year-old man was arrested in south London on Sunday, police said.
Three other men, aged 19, 22 and 26, who were arrested on Friday on suspicion of murder were released on bail on Saturday evening.
A post-mortem examination found Mr Austin-Bruce was killed by multiple gunshot wounds to the torso.
Police say they are keeping an open mind as to the motive for the shooting.
Two men wearing crash helmets were seen running away from the scene of the attack towards Alma Terrace after a series of gunshots were heard.
Officers from Operation Trident, which investigates gun crime in black communities, are investigating the shooting.