The 44-year-old guard remained hospitalized yesterday at Temple University Hospital in fair condition.
Meanwhile, police intensified their search for the alleged gunman: Jermaine Goodman, 29, who has addresses in West Philadelphia, Malvern, and West Chester.
Goodman, who also goes by the name Zahid Abdul-Muqeet, was known as a frequent shopper of the Pathmark at 4160 Monument Rd. in the River Park section, police said.
On Sunday, Goodman was picking up goods for his frail grandmother, who had given him her credit card and price-savings card to use, police said. Goodman used them, thereby leaving a trail that led police to him.
The guard, who was not identified by police, confronted Goodman about 1:50 p.m., after watching him place several items in a shopping cart and other items in his pocket, said Lt. Frank Vanore, a police spokesman.
Goodman paid for the items in the cart, which were on a list his grandmother had given him, and received $50 in cash, before leaving without paying for the items in his pocket - dental floss and cologne, Walker said.
The guard followed Goodman as he was leaving the store. Goodman noticed the guard and quickly left, leaving behind his grandmother's items in the cart, Walker said.
When Goodman attempted to get into a green van hired as a taxi service, the driver questioned why a security officer was jotting down his license-plate number and then refused to let Goodman board the van, Walker said.
Unable to leave, Goodman agreed to accompany the guard to the store's security office, Walker said. Goodman at first complied with the guard's request, taking the floss and cologne out of his pocket and putting the items on a desk, police said.
Then "he pulls a firearm and shoots him in the right shoulder and forehead," Vanore said.
Walker called the gunman a "coward" for shooting an unarmed security officer.
The gunman is seen on a surveillance video running from the security office, darting around the corner and stopping briefly to look back before tucking the gun in his back pocket and "casually" walking off, Walker said.
Police said the security officer was well-liked by his coworkers and had worked at the store for more than a decade.
Anyone with information about Goodman or the shooting is asked to call authorities at 215-546-8477 (TIPS).
Contact staff writer Barbara Boyer at 215-854-2641 or firstname.lastname@example.org.