A victim subjected to homophobic abuse by "vigilantes" in a YouTube video is crucial to a police investigation, Scotland Yard has said.
Officers investigating a string of incidents in East London where a self-styled Muslim patrol gang harassed members of the public over the weekend have appealed for the man in the video to contact them.
In the video, titled Muslim vigilantes in London harass and taunt gay male, a gang can been seen to abuse and intimidate the man using homophobic language.
They are heard to shout "get out of here you fag... don't stay around here any more".
Investigating officers from the Community Safety Unit on Tower Hamlets borough said they are unsure where and when the video took place.
In a second video, posted online, men from the gang in Whitechapel, east London, tell another man "no drink in this area, it's a Muslim area" before ordering him to pour away his alcohol.
Detective Chief Inspector Wendy Morgan from Tower Hamlets borough said: "The Met takes such homophobic behaviour very seriously.
"This man is a crucial witness in the investigation and would encourage him and anyone else with information relating to this incident to make contact in confidence as soon as possible."
Additional police patrols are being mounted across east London to reassure the public.
Two men have been arrested in connection with the investigation.
A 22-year-old man was arrested in Acton, west London on Sunday, and a 19-year-old man was arrested yesterday after going to an east London police station.
The pair were arrested on suspicion of causing grievous bodily harm and public order offences and were bailed to return to an east London police station in February and March pending further inquiries.
A police spokesman said: "The Metropolitan Police Service takes these incidents very seriously and is pursuing various lines of inquiry with a view to identifying and prosecuting the individuals concerned."