The driver, Darwin Martinez Torres, a 22-year-old construction worker from Sterling, got into an argument with a teen on a bike and then drove his car over a curb, scattering the group of as many as 15 teens, police said.
He caught up with them a short time later in a parking lot and chased them with a baseball bat, striking 17-year-old Nabra Hassanen and then abducting her in his car, police said.
Martinez Torres assaulted Nabra a second time, in Loudoun County, before dumping her body in a pond next to his apartment complex, where it was discovered about 3 p.m. on Sunday, police said. The medical examiner ruled Monday that the girl died of blunt-force trauma to the head and neck.
The horrific slaying of the South Lakes High School student reverberated beyond Virginia on Monday, as social media lit up with anger and grief, politicians expressed condolences and groups of various faiths condemned the violence.
Many feared it was another hate crime targeting Muslims, coming shortly before a man driving a truck in London plowed into a group of people who had just finished Ramadan prayers. It follows a national upswing in attacks targeting Muslims since the November election.
So far, Fairfax County police said they have no indication that Nabra was targeted because of her religion, saying her killing was probably a "road rage incident," although they continue to investigate the motivation.
"There was no indication of any racial slurs or any back-and-forth other than a verbal argument," Lt. Bryan Holland said.
The apparent lack of a hate crime offered little consolation to Nabra's family. Mohmoud Hassanen said that he and his firstborn daughter were always close. "She used to be like my friend, not my daughter," he said.
They would go out to eat together, and she would talk about her favorite music, her love of fashion, her wide circle of friends. On Monday, he was remembering those conversations and choking up. "I hope she's in paradise."
"I don't want any family to feel like what I feel now," Hassanen said. "It's too hard. I raised my daughter for 17 years. Somebody took her life for no reason."
The incident began between 2 and 3 a.m., when a group of four or five teens left the ADAMS Center during an overnight gathering to get that late-night meal, family members and police said.
Members of the mosque said it was not uncommon for young people to go to the nearby McDonald's or IHOP to eat before the Ramadan fast resumed at daybreak. The McDonald's is about a mile from the mosque.
The teens were returning to the mosque along Dranesville Road near Woodson Drive in Herndon when they encountered Martinez Torres. The road is wide at that location, with a bike lane, sidewalk and lined by trees in parts.
The ADAMS Center is near the border between Fairfax and Loudoun counties.
Tawny Wright, a Fairfax police spokeswoman, said a 911 call was placed at 4:08 a.m. on Sunday for a report of a motorist trying to run down the teens. Wright said officers were dispatched to take a preliminary report from the teens and a search was quickly launched for Nabra that eventually included dogs, a helicopter and multiple police units from Loudoun and Fairfax counties.
About 5:15 a.m., Wright said an officer noticed a car that kept circling back to the scene where the reported dispute began and where Nabra disappeared. The officer conducted a traffic stop on the vehicle.
Wright said the officer became suspicious of the driver for reasons she declined to discuss, and Martinez Torres was arrested. The search continued for Nabra throughout the day Sunday, until, Wright said, police developed information that Nabra's body was in a man-made pond near Martinez Torres's apartment building. The location is about three miles from where Nabra disappeared.
Wright said detectives are still trying to piece together what happened between the assault on Nabra at about 4 a.m. and when her body was discovered. Wright declined to say what Martinez Torres has told police and said police had found some items of evidence. It is unclear whether prosecutors from Loudoun or Fairfax will take the lead on the case because the alleged crimes in the incident crossed county lines.
Hassanen, the father of Nabra, said that he feels sure his daughter was killed because of her religion.
"He killed her because she's a Muslim — this is what I tell the detective," Hassanen said. "Why was he running behind the kids wearing Islamic clothes with a baseball stick? Why, when my daughter fell down, why did he hit her? For what? We don't know this guy. He doesn't know us. We don't hate anybody because of religion or color. I teach my kids to love everybody."
Martinez Torres was held without bond following a brief arraignment Monday in Fairfax County juvenile court. All cases involving juveniles are heard in juvenile court in Virginia, even when defendants are adults.
Appearing on a video monitor from the county jail, Martinez Torres spoke through a Spanish translator to answer a judge's questions. He was appointed a public defender, and his next court appearance was set for July 19. U.S. immigration officials requested that a "detainer" be placed on him at the county jail, meaning they are interested in possible future deportation proceedings.
Fairfax prosecutors offered no new information about the case during the Monday hearing for Martinez Torres and declined to comment afterward.
An aunt who was at the court but declined to give her name said Martinez Torres's family is shocked and mystified about the charges against him.
The aunt said Martinez Torres was at a Sterling park with her mother hours before the incident. She said Martinez Torres left the park at about 11:30 p.m. Saturday to head home.
Family members said the man worked in construction. He is Salvadoran and has a 4-year-old son and a girlfriend. He attended school briefly in the United States.
"I can't believe it," the aunt said. "He is nice with my mom. He is nice with my family. He's a nice dad."
No one responded Monday when a reporter visited a home address associated with Martinez Torres.
Neighbors who gathered in and outside the Hassanens' apartment Sunday night, both Muslim and Christian, described the teen as unusually respectful, calling older neighbors "sir" and "ma'am" and helping watch small children both at home and at the mosque.
No one could believe that the timid and conflict-averse teen would argue with a stranger on the street.
"Nabra's personality, she gets scared very easily," said her mother, Sawsan Gazzar. "Nabra doesn't even fight with her sisters. She's very scared."
Based on her conversations with detectives, Gazzar said she thought that the driver shouted at the teens and threw beer bottles at them.
Nabra's father said he tried to put that lesson " to love everybody" in practical terms, taking his four daughters to pack food for the hungry each Thanksgiving to demonstrate the importance of caring for others. Nabra learned it well, he said — she befriended everyone, Muslim and non-Muslim.
But Hassanen couldn't face the unthinkable task confronting him as a parent on Monday morning, when his youngest daughter, 3-year-old Amarose, looked up at him and asked, "Where's Nabra?"
"I don't have no answer," he said. "I just kissed her and left."
Sarah Pulliam Bailey, Faiz Siddiqui, Dana Hedgpeth and Jennifer Jenkins contributed to this report.