The victim was identified as 17-year-old Nabra Hassanen of Reston and her body was found in a pond on Sunday, The Washington Post reported.
Fairfax County police identified the suspect as 22-year-old Darwin Martinez Torres and charged him with murder.
According to accounts from police and an All Dulles Area Muslim Society (ADAMS) official, a group of four or five teenagers including Nabra had visited a restaurant to have a late-night meal after prayers during the holy month of Ramadan.
At about 4 a.m., the group was confronted by Torres as they walked on a street.
They ran into a mosque, but one of them, Nabra, was left behind and was later reported as missing, said Deputy Aleksandra Kowalski, a spokeswoman for the Loudoun County Sheriff’s Office.
The police conducted an hour-long search around Dranesville Road and Woodson Drive in Herndon and remains thought to be the girl’s were found about 3 p.m. on Sunday in a pond in Sterling.
During the search, police said they stopped a car being driven in a suspicious manner in the area, and took the driver Torres into custody.
The girl’s mother said detectives told her that Nabra was struck with a metal bat.
“I can’t think of a worse instance to occur than the loss of a 17-year-old on Father’s Day, as the father of a 17-year-old myself,” Loudoun County Sheriff Michael L. Chapman said.
The reason for the attack was still not known, but hate crime was one of the options being investigated, reports said.
“We are devastated and heartbroken as our community undergoes and processes this traumatic event,” Rizwan Jaka, chairman of ADAMS, said in a statement.
(With IANS inputs)