A woman was assaulted and pushed to the floor outside a supermarket in Northampton.
Officers in a police car were flagged down by a member of the public who reported the assault, which happened outside the Sainsbury’s on Wellingborough Road at around 4.30am on Saturday, May 27.
A man who was not wearing a shirt was seen running from the scene.
A 24-year-old man was arrested in connection with the incident, and has been released from custody pending further investigation.
The police would like to trace the witness who reported the assault, who was driving a blue people carrier or van.
Anyone with information should call Northamptonshire Police on 101 or Crimestoppers anonymously on 0800 555111.