The incident, which took place at The Crescent in Donnington, on January 14, is one of a series of car fires across the town over the last few weeks.
Officers have said they do not believe the previous incidents, which included Merlin Coppice, Thornton Park Lane, Barnes Corner in Leegomery, and The Smithfields in Newport, are connected.
The force has also been investigating after a car belonging to the far-right activist Tommy Robinson was set on fire outside the Whitehouse Hotel in Wellington on January 2.
The latest appeal relates to an incident that took place at around 10.30pm on Friday, January 14.
Officers said no one had been hurt in the fire, but that a van had been "significantly damaged".
Police said "a man dressed in black was captured on CCTV running away from the scene holding a petrol can".
Officers said that he ran towards Turreff Avenue.
Anyone with information is asked to submit it online at https://orlo.uk/9XKnr quoting incident 668 of January 14.