By Kristen Johanson

PHILADELPHIA (CBS) — “I want my mother’s killer found.”

The daughter of an elderly woman gunned down inside her South Philadelphia market on Christmas Eve is speaking out, begging the public for help to catch her mother’s killer.

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Eighty-one-year-old Marie Buck was found shot multiple times behind the counter of her grocery store near 6th and Wharton Streets on on Saturday morning, leaving a gaping hole in her daughter’s heart.

“She was an angel, my mother. She was a beautiful person. She was a beautiful woman. She didn’t deserve to die this brutally,” said Maria Buck. “She didn’t have a bad bone in her body. She was good to everybody, everybody. There was nobody that she didn’t give to.”

Buck lives just doors down from the small market that her parents owned. Her mother was set to retire in less than a month.

“My mom has been there 43 years and has never been robbed,” she said. “And my mother wasn’t robbed, except of her life.”

Nothing inside the store was taken, and investigators say they still don’t know the motive.

“She was murdered for no reason, and we want to know why. Please, if anyone knows anything, please, please call homicide, please,” Buck said.

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“We just want peace to find out why this was done to our mother.”

There is a $20,000 reward for information leading to an arrest and conviction.

Late Monday afternoon, sources in Philadelphia’s homicide unit confirmed Marie’s killing was not random. They say she was targeted.

All day Monday, family and friends stopped by to pay their respects. A few feet away, others paused to pray in front of the memorial that has overtaken the steps of Marie’s Grocery Store.

Now 48 hours and counting, the “who did it” and “why” are deeply troubling questions without answers.

“Was it something they had words over sometime or another? Or was it somebody on drugs or completely out of it?” Al Buck, Marie’s brother-in-law said.

“Who would walk in on the average and just shoot somebody like that?”

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Anyone with information about the case is asked to call Philadelphia Police Homicide Unit.