A mattress propped up against a garden shed was set alight in Wellingborough on Friday night.
Offenders set light to the mattress in the garden in Priory Road at about 10.40pm on Friday (June 16).
A police spokesman said: “The fire spread to the shed, destroying it and its contents.”
Police investigating the incident would like to speak to anyone who witnessed the incident or who has any information about it.
Witnesses or anyone with information about this incident can contact police on 101 or Crimestoppers anonymously on 0800 555 111.