Shop keeper kills robber wielding a 6-inch hunting knife

From the Philadelphia Inquirer:

. . . Police did not release the 46-year-old shopkeeper's name, but sources identified her as Sharon Doyle, who worked as a police officer in Philadelphia, Lower Makefield, and Warminster Township. She also served as a Secret Service agent from 2002 to 2004, according to a resume 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 6-inch hunting knife, said Philadelphia 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 single 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. . . . .