A straw stack was deliberately set alight in Ousden at the weekend, causing thousands of pounds worth of damage.
At 12.20am on Saturday approximately 100 tonnes of straw was destroyed in Dalham Road.
The straw - valued at £6,000 - was being stored in a Dutch barn which was also damaged in the region of £3,000.
Police are appealing for witnesses. Anyone with information should call Pc Rupert Beynon at Haverhill Police Station on 101, quoting reference HH/14/460, or Crimestoppers anonymously on 0800 555111.