Fairfax County police said the driver accused of fatally striking a woman with her SUV after a Friday traffic altercation did not intentionally run over the victim.

Gloria A. McMillan, 32, who was arraigned on felony hit-and-run Tuesday and is being held without bond, had a child and an adult passenger in her black sport-utility vehicle when the incident occurred Friday in the Mount Vernon area, police said. Both passengers, they said, are witnesses in the case.

The new details emerged as police offered their most complete account yet of the moments that led up to the death of 21-year-old Shelinda Delores Arrington, a fuller picture of the suspect came to light and Arrington’s father spoke for the first time about the tragedy.

“I was stunned and shocked,” Michael Arrington said. “She had a smile that brightened up the room.”

Arrington said he learned of his daughter’s death while he was in Afghanistan, serving a tour with the Navy. He was told by a commanding officer and boarded a plane home.

Gloria Alfreda McMillan, 32, of Alexandria, has been arrested and charged with felony hit and run. (Courtesy Fairfax County Police Department)

The encounter between two strangers — a student studying to be a criminologist and a woman with an extensive record of traffic violations and larceny convictions — began with an altercation on a busy road. But police will not say what they think sparked the argument between them.

Officer Don Gotthardt said Arrington and McMillan were driving on Harrison Lane shortly before 11:30 a.m. when both women stopped.

McMillan got out of her Chevrolet Trailblazer, approached Arrington’s sedan and the two talked, police said. McMillan then got back in the SUV, Gotthardt said. Arrington then got out of her sedan, approached the SUV and began talking with McMillan, he said.

“At some point, the suspect drove away,” Gotthardt said. “It is not clear whether the victim slipped and fell or momentum carried her under the SUV, but she was struck.”

Gotthardt added that “detectives don’t believe [the driver] intended to run over the victim.”

Gotthardt said police were able to find the SUV because they had a partial license plate number. The Trailblazer was found in Southwest Washington on Monday afternoon and police contacted McMillan, who agreed to turn herself in, he said.

McMillan, who lived near Arrington in the Alexandria section of Fairfax County, has a troubled past and has been in and out of jail, according to court records.

She was convicted of grand larceny and larceny for stealing from Target and Wal-Mart in 2007, court records show. She has also been found guilty of numerous misdemeanor offenses, including reckless driving and driving on a suspended license, according to the records.

In 2010, when she failed to tell her probation officer that she had gotten a ticket for violating a child restraint law, he required her to write a paper about following the guidelines of her probation, but she balked, according to a report the officer wrote that was filed in court. “I’m not in high school anymore,” McMillan told the probation officer, according to the report.

At McMillan’s home Tuesday, a woman who declined to be identified said her family “wanted to offer condolences to [Arrington’s] family,” but declined further comment.

Michael Arrington said his daughter wanted to go into forensic science and was planning to graduate from ITT Tech in the fall.

Staff researcher Magda Jean-Louis contributed to this report.