A feud between the grandson of an 81-year-old South Philadelphia grocery store owner and another man over a piece of jewelry ended in the well-liked woman's murder, homicide detectives said Thursday.

Suspected shooter Maurice Green, who believed the grandson stole a valuable chain from him, allegedly sprayed bullets into Marie's Grocery at S. Sixth and Titan streets just before 9 a.m. on Christmas Eve, police officials said at a press conference Thursday afternoon.

The findings were released as authorities officially charged Green, 31, with gunning down Marie Buck.

Buck was struck 11 times by gunfire, stamping out the woman's life in the mainstay she's owned for four decades.

Homicide Capt. James Clark said the suspect, who has 17 prior brushes with the law for mostly drug crimes, didn't even fully step into the store that day. Dressed in all black, he opened the door, saw the grandmother and began shooting, Clark said.

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“There is videotape of him parking the vehicle, walking down towards the store minutes before the murder, right after the murder, fleeing the scene, getting back into that vehicle and leaving," Clark said.

"We also have help from the public, we got some anonymous tips that came in, a lot of different things that tie him into the scene, some of which I won’t speak about now.”

Investigators believe Buck was not Green's original target. Clark said the suspect went to the store that day to shoot her grandson, who was due to work that day but didn't show up.

Green allegedly told investigators the grandson, who hasn't been named by police, owed him money from an expensive jewelry chain, Clark said. Green estimated the chain's value to be between $5,000 and $10,000.

Green believed the grandson and another man broke into his home, stole the chain and pawned it, Clark said. A police report was never made and police have not confirmed whether the story is true.

Working through the Christmas holiday, homicide detectives narrowed their search for the shooter this week. Green was taken into custody in city's Overbrook section Wednesday night.

He was questioned overnight and charged Thursday with murder, aggravated assault and related offenses. It's not yet clear if he's retained an attorney.

"It's one of the more horrific murders I've dealt with," Clark said.

Clark said the grandson is "very sad" and has been cooperating with police. He is not facing charges.

Family Photo | NBC10

Buck's family spent Christmas trying to come to terms with a reason that someone would kill their beloved mother -- a woman who dressed as Santa every Christmas Eve as part of family tradition -- in such a violent manner.

Buck's daughter, Maria Buck, called her mother an angel. Many people in the neighborhood called her "Aunt Marie."

"She was the kingpin of everything," said Al Buck, Maria's brother-in-law. "And my brother, he doesn't even want to live."

The family plans to close down the grocery store.

Family Photo

The announcement of Green's arrest came the same day Buck's family prepared to say goodbye to her.

Hundreds of people lined up outside Baldi Funeral Home along S. Broad Street Thursday evening to pay their respects at a public viewing.

A funeral Mass set for Friday morning at St. Mary Magdalene De Pazzi Church at 8th and Montrose streets.