Three men were knocked unconscious after a mass fight broke out in a town centre pub.
One man had to have stitches to a head wound and while two men have been arrested in connection with the brawl, police are trying to identify another man to help with inquiries.
They have released CCTV images from inside the Pier Inn pub on Pier Road and want to speak to the man with the blue shirt and white cuffs.
He is seen on the images talking with three other people at the bar, including two women and a man, then again as he leaves the pub following the fight and walks out onto Pier Road.
Police say “a number of people became involved in the fight which culminated in three men being knocked to the floor where they lost consciousness”.
It happened on Saturday April 5 at around 10pm.
One of the injured men, a 49-year-old man from Sunderland received stitches to a head wound.
Two men aged 31 and 53 from Crook in County Durham have been arrested in connection with the incident and released on police bail.
Witnesses should contact
101, select option 2 and ask for PC Ian Foley or contact Crimestoppers anonymously on 0800 555 111.