A car fire is being treated as arson with intent to endanger life.
A car outside a property in Atkinson Street, Fengate, was set alight in the early hours of Tuesday morning and the fire caused damage to the nearby building.
Scenes of crime officers attended the incident and a police spokesman said it is being thoroughly investigated.
Police were called by Cambridgeshire Fire and Rescue Service at 4am to a suspected arson attack.
Anyone with information should contact police on 101 or Crimestoppers anonymously on 0800 555111.