In her Overbrook bedroom, Denise Williams had 15 shopping bags of presents for her grandchildren, which she planned to give them when they celebrated together the day after Christmas.

Williams never got to deliver her gifts.

On Thursday, police identified the 54-year-old grandmother of six, who worked as a security guard at the Philadelphia Museum of Art, as the fatality in a Christmas night hit-and-run in Kensington.

Just after 8, witnesses said, Williams was sprawled on the sidewalk in the driveway of the closed Family Dollar store on Frankford Avenue.

She looked sick or debilitated, they said. But before anyone was able to help her up, a black Dodge Charger turned into the otherwise-empty parking lot, running her over.

The driver, described as a woman in her 40s, walked toward Williams, but got back in her car and drove away, witnesses told police.

Williams died of head trauma at Temple University Hospital.

Police have released surveillance footage of the car but have not identified the driver. With a medical examiner's report pending, investigators do not know how Williams, who was alone, wound up on the pavement - if, for example, she had fallen ill in the moments before her death.

Williams' housemate and "god-sister" Bernice Dawson, 67, said Thursday that Williams had gone to Kensington on Christmas for a holiday dinner with her boyfriend, who lived in the neighborhood. She last spoke to Williams by telephone on Christmas morning. She did not know where the couple were heading for dinner.

Dawson had shared her Overbrook rowhouse with Williams for five years. She said the two were lifelong friends.

"She was happy here," Dawson said, recalling Wilson as a "sociable person who loved being around people, talking and laughing."

Williams worked for an agency that provided security guards to the Art Museum, sometimes doing six or seven shifts a week, Dawson said.

"She was a working person," she said. "Any time they called her, she'd go in. She'd go in on her day off."

She also liked to shop. Shoe boxes lined one wall of her bedroom, and she was meticulous about coordinating her outfits. If she wore a blue jacket, she made sure to have matching blue shoes and a bag, Dawson said.

Family and friends often called Williams, petite with short hair, by her childhood nickname, "Peanut."

She had two grown children and enjoyed '60s oldies music, Judge Judy, and Atlantic City trips to see the Temptations. She often surprised Dawson's grandchildren with candy. She took SEPTA everywhere and enjoyed Ballantine beer.

On Christmas Eve, Williams and Dawson ate shrimp and fried crab cakes and played pinochle by the Christmas tree.

Williams had gotten her nails done for her Christmas date.

"She was excited about Christmas," Dawson said.

On Wednesday, Williams' daughter came by to collect some of her mother's belongings. She made sure to take the bags of presents Williams had bought for the children.

Authorities ask that anyone with information call the Accident Investigation District at 215-685-3180.

Contact Mike Newall at 215-854-2759 or mnewall@phillynews.com.