Two “heroic” skateboarders stepped in to help police restrain an alleged murderer after a fatal stabbing in Oxford Street on Thursday.
Detectives in the case have released an image of the two men, who did not stay or speak to police at the scene, and have called for them to come forward.
A 60-year-old man was attacked shortly before 8pm on July 1 and later died as a result of the knife-inflicted injuries.
Tedi Fanta Hagos, 25, of Ravenhill, Swansea has been charged with murder.
The two men appear to be skateboarders and one used his skateboard to help apprehend Hagos - who did not sustain lasting injuries - following the attack.
Police say their role only came to light following a review of CCTV and other video footage of the incident.
Detective Chief Inspector Vicky Tunstall, who is leading the investigation, said: “In addition to being immensely brave, we believe these two individuals may also be key witnesses.
“In stepping forward as they did to apprehend a violent individual, they showed great courage and potentially prevented others from being attacked.
“I want to be clear that while they used force to subdue the attacker, those actions were entirely reasonable and are not in question.
“They can be assured that we wish to speak to them solely as witnesses.”
Police are asking the men to contact the Met’s incident room on 0208 785 8099.