Police are hunting suspected arsonists after three cars caught alight on a garage forecourt.
The incident happened at around 11.30pm last night at GMD car sales in Carville, near Durham City.
Although no one was injured, it is believed about £16,000 worth of damage has been caused.
A joint investigation between police and the fire service is underway and officers are keen to hear from anyone with information.
Durham Police can be contacted on 101.