Police believe this man may have been a key witness to a fight in Northampton town centre which left a 61-year-old fatally injured.
It is thought George Wedderburn, of Byfield Road, St James, was injured after intervening in the fight at Abington Square in the early hours of last Sunday.
He died six days later in hospital.
Police have released this image of a man they think may have tried to act as a peacemaker.
Officers would like him or anyone who knows him to contact them on 101.
Daniel Tero, 22, of Burleigh Road, Kingsthorpe Hollow, has been charged with assault.
He is due to appear at Northampton Crown Court on Wednesday September 3.
More top news
Britain has seen its driest first half of September since before the 1960s and it's also been rather warm.
Low cloud will once again spread across the region. Mist and fog reforming
Police are appealing for information following the disappearance of one of the UK's rarest birds of prey in the Great Bircham area.