Tyrone Pinnock, 36, died after being stabbed in Kensal Road, Kensington and Chelsea, on Thursday (October 19).
Detective Chief Inspector Neil Rawlinson, leading the investigation, said: “This happened in the early evening on a busy footbridge that crosses Harrow Road.”
That day at 6.42pm, a police car was flagged down by a member of the public who had found a man with stab injuries in Kensal Road.
Officers carried out first aid and called for support from the London Ambulance Service.
Despite their efforts, the Tyrone died at the scene.
Formal identification awaits, police said, but Tyrone’s family have been informed and are being supported by trained officers.
There have been no arrests at this time.
Det. Ch. Insp. Rawlinson added: “Several people have spoken to us already and I want to hear from anyone who saw the incident or has any information that could help our investigation.
“Were you travelling on Harrow Road between Bravington Road and Third Avenue between 5pm and 7pm?
“If so we would like to hear from you and view any dash cam footage you may have.”
Anyone with information about the incident is asked to call 101 quoting CAD 6212/19Oct.
To remain anonymous contact the independent charity Crimestoppers on 0800 555 111.