WASHINGTON — Montgomery County police are asking for the public’s help in identifying a suspect in a case of credit card fraud.

On Aug. 18, a woman went to the Cosi restaurant on Woodmont Avenue for dinner and slung her purse over the back of her chair, police said. Hours later, she was contacted by her bank: Her credit cards had been used. She immediately checked her purse and found her wallet gone.

Montgomery County Police Officer Rick Goodale said the suspect apparently used the card at a Target store in Rockville and at stores in Westfield Montgomery Mall, racking up $12,000 dollars in purchases.

Police have released images of the suspect from surveillance footage and are asking anyone with information about the case to contact them.

Goodale said the case is a reminder that no matter where you are, even in familiar surroundings, you need to keep an eye on your wallet or purse. “For men, we suggest keeping the wallet in their front pocket or jacket pocket, and for ladies, we suggest keeping your purse between your feet,” he said.

There has also been an increase of thefts from cars in the Bethesda area, Goodale said. He reminds residents to lock their cars and to be sure not to leave valuables in them, even if the vehicle is locked. Visible items can tempt a thief into breaking a car window to access them.

“Theft from autos and vehicle theft continue to be a high-volume crime in Montgomery County,” he said.

One thing Goodale said officers frequently see — residents who leave garage doors open and keep spare car keys hanging from a hook in their garages.