Police say there has been a marked increase in the number of purse thefts in supermarkets in Grantham.
People have reported they have been approached and spoken to by a young female and while they have been distracted their purses have been stolen from their bags.
Thefts have also taken place while people are away from their trolleys and have left handbags and contents unattended in the trolley.
A police spokesman said: “Please do not leave valuables unattended and do not write your PIN down and leave it in the purse, with your cashcard.”
He added: “There have also been a number of thefts from vehicles whilst parked in dog walking areas or tourist attraction areas. Please be vigilant and DO NOT leave property on display.”
If you see anything suspicious call the police on 101.