Shortly before 3.40pm on Sunday 6 October 2013, police were called to the canal at the junction of Princess Street and Canal Street in Manchester city centre following a report there was a body in the water.
The body of Sean Michael Markey, 39, from Newton Heath, was recovered later that day.
A post mortem examination into his cause of death was inconclusive and further tests are being carried out.
A police investigation is ongoing to trace Sean’s last movements and ascertain the circumstances surrounding his death.
As part of these enquiries, officers have established that Sean was last seen walking down Princess Street with a man at around 4.15am on Wednesday 2 October 2013, before the pair were seen walking onto the canal banking area near to the New Union bar.
Further CCTV enquiries have subsequently shown another man walking from the canal banking area shortly after 4.40am on 2 October and police are keen to speak to this man to find out if he saw anything.
Senior Investigating Officer Andy Tattersall said: “Sean’s family have understandably been devastated since his death and we have been carrying out a full and thorough investigation to find out exactly what happened that morning, so we can provide his family with the answers they so desperately want.
“We are today releasing new CCTV footage of a man we would like to come forward and speak to us, as he was in the area of the canal not long after Sean and the other man were last seen, and may have seen or heard something that could be of great importance to our enquiry.
“We have also issued some CCTV that we believe is this same man walking near to the bars shortly before he went into the canal area. If you recognise yourself from this footage, then please get in touch and help us piece together Sean’s final movements.”
A 27-year-old man who was arrested by police in connection with this investigation remains on police bail until 10 March 2014.
Anyone with information should call police on 0161 856 2448 or contact the independent charity Crimestoppers, anonymously, on 0800 555 111.