The attack happened in the Clanmorris Close area of Bangor on Saturday 14th July.
Police received a report shortly before 2.20 am that a parked white van was on fire in the area.
Northern Ireland Fire and Rescue Service attended and extinguished the fire.
There were no reports of any injuries, however, extensive damage was caused to the vehicle and its contents.
Detectives are appealing for anyone who witnessed the incident or may have seen anyone or any vehicles acting suspiciously in the area to contact them at Bangor Police Station on 101 quoting reference 158 14/07/18.
Alternatively, information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.