A police patrol car was set on fire in Daventry in the early hours of Tuesday, November 10.
The vehicle was parked near Danetre Vauxhall off London Road, when at about 1am reports were made that it was on fire.
The fire service was called out, but the police car was largely destroyed by the blaze.
On Twitter several police officers pointed out that such cars are a limited resource for the police, and putting this car out of action could impact on the safety of other victims of crime.
Officers said two males had been spotted leaving the area, and that they were looking at CCTV images.
Anyone with information should call Northamptonshire Police on 101.