D.C. police on Tuesday identified a person killed during a shootout with officers as a 21-year-old woman and said her male companion has been charged in what authorities think was an interrupted holdup of a liquor store.

Police said Marquesha McMillan of Northeast Washington had opened fire on officers Monday morning in the parking lot behind Morris Miller Wines and Liquors, at Alaska and Georgia avenues NW. Ned McAllister, 21, also of Northeast, who police said fled from the scene, has been charged with burglary while armed.

Witnesses described a fierce and prolonged gun battle between several officers and a woman taking cover behind a trash bin. One witness said that she heard as many as 30 gunshots. D.C. police Chief Cathy L. Lanier said McMillan reloaded her gun twice before she was killed.

McMillan’s aunt, Stephanie Chambers, 36, questioned how a charter school graduate who attended college and worked as a janitor at FedEx Field could have gotten mixed up with a liquor store robbery.

Chambers said the family didn’t think McMillan had experience with guns.

“She’s not familiar with nothing like that,” said Chambers, who lives in Northeast. “I don’t know if she had a gun. I don’t know why she was shot by police. I don’t know where on the body she was shot. What I do know is that all of this is out of character.”

McMillan wrote on her LinkedIn page, and Chambers concurred, that she graduated from a charter school and attended classes at the University of Maryland Eastern Shore, where she studied exercise science. A university spokesman could not confirm that account Tuesday night.

Chambers said that McMillan played basketball in school and “had a bright future.” She said that her niece left college before graduating to live with family in North Carolina, where she worked at Wal-Mart. McMillan returned recently to the District and a new job at the football stadium, her aunt said.

McMillan has no criminal record in the District and has one arrest in Maryland for assault and resisting arrest, a case prosecutors did not pursue. Chambers said that relatives had never heard of McAllister.

The incident at the liquor store, which is near the Maryland border, occurred just after 9 a.m. Monday. Police said McMillan was wearing a dark jacket, dark hooded sweatshirt, gray pants, white and red shoes, and a dark item covering her face. McAllister was armed with a long-barreled gun, and he wore a dark hooded sweatshirt, a yellow construction vest, black pants and gloves, police said.

Prosecutors said in an arrest affidavit that McAllister and McMillan walked into the store, passed an employee sitting in an office and entered a stockroom. The document says that McAllister tried to lock the store’s doors but failed.

Lanier said he was trying to lock in the worker. “They were definitely going to rob the joint,” the chief said. “Both go in with masks on their faces and guns in their hands.”

But when a second worker arrived, Lanier said, McAllister and McMillan fled.

Police said McAllister left through the back door and McMillan exited through the front. A police officer chased her to the parking lot, where police said she fired on officers, who fired back.

By the time police found McAllister in a nearby alley, he had discarded some of his clothing; the yellow vest and other items were found in a gray Buick parked near the liquor store, police said.

Also in that vehicle, police said, was a black Taurus .38-caliber revolver loaded with five bullets and tucked under a seat, along with white and gray gloves, a black hooded sweatshirt and a black ski mask.

Magda Jean-Louis and Victoria St. Martin contributed to this report.