A dog died after being trapped in a car which was set on fire in Wellingborough.
Police were called to Minerva Way at about 1am on Sunday, October 11, where a Vauxhall Astra was alight.
A lurcher was later found dead in the vehicle.
Officers had earlier attended the same location at 11pm on Saturday, October 10, where a Fiat Stilo had been set on fire.
Police are linking the incidents and are urgently appealing for witnesses to come forward.
Witnesses or anyone with information should contact police on 101 or Crimestoppers anonymously on 0800 555111.