By her mother’s account, 53-year-old Tonya Reaves rode her bike everywhere, no matter the time of day. Donna Hill said her daughter used to pedal home when she got off late from her former job at Pizza Hut, and she would frequently bike to her boyfriend’s house or even just for fun.

It’s not clear where Reaves was going — or what she was doing — on the September morning when she and her bike crossed paths with a car full of people who seemed to have come from a U Street bar. Perhaps the only thing that is clear about the encounter is that the car hit Reaves and then drove away.

On Wednesday — almost a month after the incident — police charged the car’s alleged driver, DaJane Thomas, 20, with second-degree murder in connection with Reaves’s death. Although witness accounts in court papers have shifted and are contradictory, two people said that the young woman studying to be a surgical nurse or nursing-home worker ran over Reaves slowly after striking her, inflicting gruesome and fatal injuries.

“If I had a chance to talk to her, I would just like to ask her, ‘Why?’ ” Hill said.

Hill said that Reaves — whose 30-year-old son, John Arthur Reaves III, was fatally shot in 2009 — was a doting daughter who would frequently seek her parents’ advice. Reaves recently had been laid off from a fast-food job and had had an interview lined up for a new position the Monday after her death, her mother said. She planned to go to her parents’ home that weekend to polish up her résumé.

“She had a wonderful personality,” Hill said. “She was just a joy to be around.”

Hill, 72, said she got word of her daughter’s death early Sept. 20, when a detective rang the doorbell at her Northeast home. She said the detective told her that her daughter had been killed in a hit-and-run crash that morning and asked where Reaves, who also lived in Northeast, might have been going on her bike. Hill said she did not know.

“That is a question that I can’t answer,” she said.

The investigation proved complicated, as witnesses’ stories to police shifted in the days that followed, court papers show.

When police arrived at Eighth and S streets NW, they found Reaves’s bicycle in a crosswalk and two apparent witnesses, one of whom claimed to have been on foot while observing a sport-utility vehicle hit Reaves, according to a police affidavit. Both people would later admit to being in the vehicle that hit Reaves and claim that Thomas was driving, although one first pointed to another person as the driver, according to the affidavit.

Investigators tracked down four people who claimed to be in the car during the crash, and all four alleged that Thomas was the driver, according to the affidavit. One person told investigators that the group had just left the New Town bar on U Street and that Thomas had been drinking, according to the affidavit.

But that account was backed up by only one person, who claimed that Thomas was drinking vodka and lemonade and smoking marijuana, according to the affidavit. The two others in the car said that Thomas was neither drinking nor smoking, according to the affidavit.

When police searched the car, a Ford Focus, that they believe was involved in the crash, they found a nearly empty bottle of vodka, according to the affidavit. Police said Thomas did not have a driver’s license.

Bernard Grimm, Thomas’s attorney, said that Thomas was a T.J. Maxx employee and a student at Medtech who was aiming to become a surgical nurse or nursing-home employee. He said that Thomas, who is not in police custody but is being monitored electronically, did not encourage anyone in the car to lie to investigators and said she and her family sought his legal advice soon after the crash.

“In these cases, this is sort of trite, but there are no winners,” he said.

Hill said she has been haunted by the crash. She said she is particularly troubled by the allegations of drug and alcohol use and that whoever hit her daughter drove away.

“Have you ever considered how you would feel if someone hit your child and left them for dead and never stopped?” she said. “It’s horrible.”

Magda Jean-Louis contributed to this report.