Police have released images of two people they want to speak to about a "vicious" homophobic attack in which up to 20 people left a man unconscious.
Jean Claude Manseau and a friend were reportedly subjected to homophobic abuse after the pair sang songs on a Manchester tram in the early hours of Saturday November 1.
A man followed Manseau as he left the tram at Manchester Piccadilly tram stop, before a group of between 10 and 20 people attacked the 25-year-old at around 1am.
Manseau was "badly beaten" and required stitches to his faces after the attack.
The violent assault sparked a protest movement in the city, with hundreds of people taking part in a mass singalong on trams.
Detective Constable Tim Greenwood, of Greater Manchester Police, said: "We are treating this as a homophobic assault as the men made homophobic comments to the victim as they attacked him.
"The attack was totally unprovoked and the message is clear - we simply will not tolerate it.
"The victim was badly beaten and had to have stitches to his face, as a result of this vicious attack. He was understandably very distressed by what happened and specially trained officers have supported him.
"We want to speak to the man and woman pictured in the CCTV images who may have vital information that would assist us with the investigation.
"I would urge anyone who witnessed the incident or has any information about what happened to contact police immediately."
Anyone with information have been urged to call police on 0161 856 3229 or independent charity Crimestoppers on 0800 555 111.