A man was assaulted during an evening attack while he was walking through Northampton town centre on Monday (July 31).
The 37-year-old man was walking along Sheep Street when three men walked past him, travelling in the opposite direction.
A member of the group punched the victim to the side of his face before chasing him towards Greyfriars.
A spokeswoman for Northamptonshire Police today said: "Officers would like to speak to anyone who may have witnessed this incident, which took place at about 6.30pm.
"The offender was white, around 40, 6ft, of athletic build and wearing a light coloured t-shirt."
Witnesses or anyone with information about this incident can contact police on 101 or Crimestoppers anonymously on 0800 555 111.