Firefighters suspect arson following a spate of vehicle fires in Chesham in the early hours of Saturday morning.
Police are working with the fire service "to establish motive and any possible suspects" after a lorry and two cars are believed to have been set alight over the weekend.
Bucks and MK Fire tweeted: "Firefighters attended three deliberate vehicle fires in Chesham this morning. Know anything about them? Ring 101.
A crew from Amersham was called out on Saturday (March 25) to Shortway, Chesham, at around 4.40am.
Luckily the fire was out on arrival.
A crew from High Wycombe was called out to Pearce Road, at around 3.48am.
Firefighters used one hose reel and one set of breathing apparatus.
And firefighters from Amersham and Berkhamsted tackled a car fire which spread to a hedge on Lyndhurst Road at around 3.24am.
They used two hose reels and one set of breathing apparatus.
Superintendent Yvette Hitch tweeted on Saturday (March 25): "Currently working with bucksfire to establish motivate and any possible suspects. Lots of police and fire activity."