A 22-year-old man was killed when his moped crashed into a tree in East Dulwich on Monday.
Officers are now appealing for any witnesses, including those with dashcam footage, to come forward as they try and piece together what happened during the incident.
The fatal collision took place at around 9.15pm on July 20 in East Dulwich Grove.
The rider had been travelling in the direction of Thorncombe Road when he collided with the tree.
He died at the scene and, although he has not been named, his next of kin have been informed.
The Met says it is still unsure if any other vehicles were involved.
Anyone with information should call the Serious Collision Investigation Unit at Catford Traffic Garage on 020 8285 1574.