Typically on Christmas Day, Marie Buck would delight relatives by donning a Santa costume and distributing presents.

This Christmas, the South Philadelphia shop owner's family is in mourning and stunned disbelief over her vicious killing Saturday in her small grocery store.

Police said the 81-year-old who seemed to take a personal interest in her customers, including helping those in need, was gunned down shortly before 9 Christmas Eve morning by a male dressed in black and wearing a hood.

Marie's Grocery, at Sixth and Titan Streets, has been owned by Buck and her husband, Michael, for 44 years.

Police said they found Buck lying behind the service counter with several gunshot wounds to the torso. She was taken to Jefferson University Hospital and pronounced dead at 9:12 a.m. There had been no arrests as of late Saturday night and nothing was reported stolen.

Gathered at the couple's home, several doors down on the 1200 block of South Sixth Street, her grandniece, Angela Sweeney, said the family was "devastated and in shock."

"We are trying to hold it together," she said.

Buck was beloved by her family, said Sweeney, who recalled her great-aunt's role playing as Santa each Christmas and her far-reaching generosity.

"She was loved," Sweeney said. "People who moved away would come back to visit her. If you walked into her store, she would feed you without hesitation if you had no money."

And she took no customer for granted, said Kristin Guessford, who lives around the corner from Marie's.

"She was so sweet, so kind. She remembered us every time we walked in," Guessford said.

Added neighbor Rory Cain: "We were just talking to her about Christmas, and she said, 'I love Christmas, but Christmas is hard when you get old.'"

Guessford and Cain said that they felt reasonably safe in this neighborhood, though "every once in a while you see a shady character walking around."

Buck's daughter, Maria Buck, told 6ABC she did not think her mother's killing was random, that someone was stalking her.

In 2013, Buck told WHYY that the clientele at her store was shifting as new people moved into the neighborhood. Her store once provided fresh foods, but had lately shifted to canned staples due to demand.

"No one wants to cook anymore! But at least it's good for business," Buck told WHYY.

After news of the shooting spread, Philadelphia District Attorney Seth Williams tweeted:

"My thoughts & prayers are w/the family, friends & those effected by the horrific shooting & murder of the 81yro woman in SPhilly this morning."