Officers were called at approximately 9pm on Thursday, 25 June to reports of a collision involving a car and cyclist on Streatham Hill, at the junction with Telford Avenue.
A silver VW Tiguan travelling towards Streatham South was involved in a collision with a cyclist.
Officers from the Roads and Transport Policing Command are investigating.
They are particularly keen to hear from any motorists who were on Streatham Hill at approximately 9pm and who may have recorded the events leading up to the collision on dashcam.
Any witnesses yet to speak with police are asked to call the Serious Collision Investigation at Catford on 020 8285 1574 quoting reference Cad 8825/25Jun.