A police car was set on fire in Daventry yesterday evening with officers calling the attack "unacceptable" and "disgraceful".
The response team's car was parked in Trafalgar Way in Southbrook when it was targeted while an officer attended an incident.
The car, which is in constant use by the police, had its rear windshield smashed.
"It's unacceptable to set any car on fire but to set fire to an emergency service vehicle, a vehicle that we use 24/7 to attend incidents to protect and help people, is disgraceful," the response team tweeted.
The attack was also condemned by Daventry Neighbourhood Sergeant Sam Dobbs.
He tweeted: "This is a police car but it effectively belongs to us all.
"Its replacement will come from the public purse.
"Stupid, senseless, mindless, reckless criminality which hampers emergency responders."
Anybody with any information please should call 101 and quote NP-20181209-0461, or call Crimestoppers anonymously.