A thief stole a bag containing a mobile phone and a small portable TV from an unlocked car parked in Louth on Wednesday.
The theft happened as the car was parked in Aswell Street between 5.30pm and 11.30pm on March 27.
The offender(s) entered the gold Rover 25 taking a camouflage-patterned bag containing the items.
Anyone with information should contact PC Jon Best at Lincolnshire Police by dialling 101 and quoting incident 142 of March 28.
Police want to remind motorists of the importance of always keeping vehicles secure and removing items of value from view.