A driver has died after being struck by two cars following a row with another motorist, police said.
The 40-year-old was found at the junction of Trinity Road and Magdalen Road, in Wandsworth, late on Friday. He had earlier been assaulted.
The victim, in a Nissan Micra, and the driver of a Ford Fiesta had pulled up at the scene and were involved in an altercation, police said.
The victim was then hit by two other cars that failed to stop at the scene.
A 25-year-old man was arrested on suspicion of assault and officers are also looking for the drivers of the two vehicles which struck the victim.
The Metropolitan police is yet to formally identify the victim. His next of kin have been informed.
A Met spokesman said: "At this early stage, it is believed that the man was the victim of an assault prior to being in collision with two vehicles that failed to stop at the scene.
"A 25-year-old man has been arrested on suspicion of assault and is in custody at a south London police station."