Officers were called at approximately 23:50hrs on Thursday, 6 August to reports of a collision between a van and a car in Pembridge Villas, W11.
London Ambulance Service also attended the scene and a man, no further details, was pronounced dead at the scene shortly after 01:00hrs on 7 August.
Enquiries are underway to establish his identity and inform next of kin.
At this early stage it is believed that the van had broken down in Pembridge Villas and the driver had got out of the vehicle. The car, a silver Bentley, was then in collision with the lorry and the driver.
The two male occupants of the Bentley – an 07 plate Continental GT – were witnessed to get out of the car and run from the scene – one along Pembridge Villas towards Westbourne Grove, the other along Dawson Place. Enquiries continue to trace them.
Officers from the Serious Collision Investigation Unit based at Merton will investigate.
Anyone with information is asked to contact the witness appeal line on 020 8543 5157 or call police via 101. Alternatively, contact Crimestoppers anonymously on 0800 555 111.
No arrests, enquiries continue.