Man dies at St John's car park in Northampton
A 55-year-old man collapsed and died following a "verbal altercation" with another man at a Northampton car park.
Police said they wanted to hear from anyone who saw a dispute between two drivers leading up to the argument at St John's car park on Saturday morning.
A 40-year-old man was arrested after the incident at about 1035 BST at the open air car park in St John's Way.
Det Ch Insp Martin Kinchin from Northamptonshire Police said he wanted to hear from witnesses.
"The car park was very busy on Saturday morning and I am keen to speak to anybody who witnessed this verbal altercation.
"We are also keen to speak to anybody who may have witnessed a dispute between a blue Toyota Yaris and a bronze 3 series BMW on Bedford Road immediately prior to this incident."
Northamptonshire Police said they were not looking for anyone else in connection with the case.