Thieves have stolen a brass whistle from a steam traction engine at the Museum of East Anglian Life in Stowmarket.
The theft took place between Sunday May 8 and Friday May 20 at the museum on Iliffe Way.
The eight inch long brass whistle has a thread at the bottom where it attaches to the engine.
Witnesses or anyone with information are asked to call Suffolk police on 101 reference 37/34263/16.
Alternatively, contact Crimestoppers anonymously on 0800 555 111 or through their anonymous online form at www.crimestoppers-uk.org