A car was set on fire on the Southbrook estate in Daventry on Sunday.
The arson attack happened in Vernon Close between 10.30pm and 10.40pm on April 9.
The offenders smashed the rear window of a silver Vauxhall Vectra before setting fire to the vehicle and running off.
Significant damage was caused to the inside of the car and further damage by a nearby resident and police using a fire extinguisher to put out the blaze.
Anyone with information can call Northamptonshire Police on 101 or Crimestoppers on 0800 555111.