A £50,000 reward has been offered by detectives investigating a fire in Manchester's Chinatown that killed two people who had been sleeping rough.
The blaze in a disused building in Nicholas Street began early on 25 November and burned for several hours.
The bodies of Wayne Bardsley, 51, and James Evans, 57, who had taken refuge in the building, were found inside.
A 24-year-old man, who was arrested on suspicion of murder, has been bailed pending further inquiries, police said.
Det Ch Insp Amber Waywell said: "This is a complex investigation and we need the public's help to fully understand how these two men lost their lives.
"I'm hoping the reward of £50,000 will help you come forward with information which will lead to a successful conviction.
"Anything you know, no matter how insignificant it may seem, could prove to be the vital piece of the jigsaw."