The body of a man has been recovered from a stretch of canal in the city centre of Manchester.
Police were called to an area near to Ducie Street at about 0210 BST after reports that a man had been seen in the water.
An underwater search team went into the canal and found the body.
Detectives are treating the death as suspicious. The man has not yet been identified and a post-mortem examination will take place later.
Police said the inquiry was still in its very early stages and they were not willing to speculate about what caused the man's death.
But the investigating officer said it was imperative that witnesses did contact them.
Det Insp Janet Hudson, said: "We know that this particular area of the canal is sometimes used by men looking for sex with other men and therefore some witnesses may be reluctant to come forward.
"But you could hold vital information which could help us build up a picture of what happened to this man and I would therefore urge you to come to us. We are not interested in why you were there, only what you saw.
She added: "You can come to us in confidence and we will treat you with discretion and respect."