Police are trying to piece together Mr Lynch's last movements
Detectives investigating the death of a man who drowned in a Manchester city centre canal are still trying to trace the man who alerted emergency services.
The body of Alexander Lynch, known to friends as Jimmy or Sandy, was found near Ducie Street early on Friday. He was last seen nine hours earlier.
Police say the man who alerted the fire service could have vital information but has yet to come forward.
They pledged that any information would be treated with sensitivity.
The area is sometimes used by men looking for sex and detectives believe that witnesses may be reluctant to come forward.
Police are also trying to account for Mr Lynch's final movements and say he had changed clothes since he was seen at Stockport railway station at 1710 BST on Thursday.
Mr Lynch's body was pulled from the water at 0200 BST and although there were no obvious signs of trauma, detectives are treating his death as suspicious.
Det Supt Julian Ross, of Greater Manchester Police's serious crime division, said: "There is a large part of Jimmy's evening we have not been able to account for and it is important we find out what happened to him during this time if we are to establish how he came to be in the water.
"I understand this area is sometimes used by men who are looking for sex with other men and there may be reluctance from potential witnesses to come forward, but I would like to reassure these people that we will treat any information we receive with sensitivity."
He said it was particularly important the man who called the emergency services came forward.
"I want to reiterate we are not interested why you may have been in the area, only what you may have seen," he added.