North Wales Police are looking to trace the man depicted as a potential witness to the murder of Craig Harold Maddocks in the early hours of the 26 June 2013 at the Cambrian Vaults public house in Wrexham.
The man, who is not a suspect, is the only person who has not been traced from CCTV footage inside the pub.
He was in the public house around the relevant time of the incident and police believe he may have information that would assist their investigation.
DC Andy Crawford said: “We are keen to trace this man who is not a suspect, but who may hold vital information. I would urge the man himself to come forward or anyone with knowledge of his identity to contact North Wales Police on 101 or Crimestoppers anonymously on 0800 555 111.”