A man in his 50s is said to have been assaulted by a driver at a supermarket car park in Downham on Saturday (February 4).
Police are appealing for witnesses to the incident, which happened at about 11.25am in the Tesco car park, following a near-miss between a pedestrian and a vehicle at a zebra crossing.
Following this, the driver reportedly got out of the vehicle and verbally threatened the pedestrian before assaulting him.
The victim, a man in his late 50s, suffered bruising.
Two members of the public intervened and officers are keen to trace these people as well as anyone else who may have witnessed the incident.
Anyone with information should contact PC Hayley Williams at the Lynn Police Investigation Centre on 101 or call Crimestoppers anonymously on 0800 555 111.
A man in his 20s has been arrested in connection with the incident and questioned.
He has been released on bail until February 28 while enquiries continue.