A former Philadelphia police officer shot and killed a knife-wielding man who tried to rob her vitamin store Monday evening, police said.

Police did not release the 46-year-old shopkeeper's name, but online business records identified her as Sharon Doyle, who worked as a police officer in Philadelphia as well as Lower Makefield and Warminster Townships. She also served as a Secret Service agent from 2002 to 2004, according to a resumé posted online.

She was behind the counter of Stan's Health Foods, on the 7100 block of Frankford Avenue in Mayfair, just after 5 p.m. when a 47-year-old man walked in and brandished a six-inch hunting knife, said Inspector Scott Small.

"No other employees, no customers," Small said. "Just her and the robbery suspect."

The man went behind the counter and threw the cash register on the floor to break it, Small said, then began collecting the money scattered on the floor. He then put the knife to the woman's chest, Small said, and she sprang into action.

She drew a gun and fired a shot into the man's chest, Small said. The man collapsed on the floor.

When police arrived moments later, the suspect was still clutching some cash in his left hand, Small said. A knife was found nearby.

The man was pronounced dead shortly afterward at Aria Health-Torresdale Campus. His name has not been released.

Doyle was not injured. Detectives are conducting a full investigation into the shooting, Small said.

The store, which specializes in bodybuilding and weight-loss supplements as well as vitamins and other products, has been in business for more than 30 years. It was started by two brothers, according to its website.

Several neighboring business owners said they were shocked by the news, and declined to comment further.