Residents are being urged not to leave doors and windows insecure during the warmer summer months.
The Lincolnshire Police warning comes after an attempted sneak-in burglary in the early hours of the morning in Spalding.
The burglar attempted to gain access through an open window at a property on Park Road between 5.30am and 5.45am on Sunday, May 14.
However, he was disturbed by a neighbour and left empty-handed.
Anyone who saw suspicious activity around that time should call DC Keith Spicer at Spalding CID on 101, quoting incident number 93 of May 14.