Lives could have been put at risk when a doormat was set on fire, police said.
The fire was started on the doorstep of a property on Malthouse Court between 3am and 3.15am on Saturday.
Detective Constable Claire Fox said: 'Whilst only a doormat was damaged in this incident, there was potential for this fire to take hold and lives could have been at risk. I want to speak to anyone who may have seen anyone acting suspiciously in this area in the early hours of Saturday morning, particularly a man who was seen nearby who we would like to speak to.'
Anyone with information should call DC Fox at Thetford CID on 101 or Crimestoppers, anonymously, on 0800 555 111.
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