Police call them a "crime of opportunity."

A person may be in a public bathroom or studying at a college library or drinking a cup of coffee at Starbucks. They did not set out that day to commit a crime, but time's may be tough and they stumble upon a unmanned laptop or an open purse.

Within seconds a choice is made and a crime committed.

Over the past few months Radnor Patch has reported on a number of such crimes: in a Villanova University bathroom, where a woman accidentally forgot her computer; in the law school library, where someone left their laptop briefly to get something to eat.

Most recently, it happened on Wednesday, June 6 at about 3:30 p.m. at Starbucks in Wayne, where a woman took a phone call and left her purse and computer unattended.

A debit card and a credit card were taken from her purse and used on more then $1,700 worth of goods at the King of Prussia mall by the next day.

The victim told police that a white man in his 30s wearing a button down shirt had been sitting next to her. When she returned from her phone call he "suddenly left the store," she said.

Radnor Police ask that the public reduce these "crimes of opportunity" by not providing the opportunity to people: Don't leave expensive items in your parked car. Lock your car when it is parked. And keep your purse on you in public.

Do you have any other tips to share on how to avoid becoming a victim of theft?