The police in Northern Virginia are investigating a report by a black 12-year-old girl that three white boys in her grade held her down, covered her mouth and cut off lengths of her dreadlocks on a playground at their private Christian school.

The girl, Amari Allen, who is in sixth grade, and her family spoke to media organizations this week about what she said happened to her on Monday on the playground of the school, Immanuel Christian School in Springfield.

“Sometimes I think that I don’t deserve to be there at a Christian school and everything,” Amari said in an interview with WUSA9. “All three of them around me. And one of them kept putting my hands behind my back. One of them covered my mouth.”

The third student then pulled out scissors, Amari told the TV station. He “took, like, big chunks of my hair, just cut,” she said. The girl said a teacher was “assessing another situation” and did not see what was happening.

On Friday, Chief Edwin C. Roessler Jr. of the Fairfax County Police Department said in a statement, “We are actively investigating an alleged assault on Sept. 23 at the Immanuel Christian School.”

He said his department was prohibited from providing further information because the incident involved children.

Asked about the allegations earlier Friday, Sgt. James Curry, a spokesman for the department, declined to discuss details of the investigation, such as whether there was video, but added that the police were informed of the incident Wednesday.

Interviews and details about the alleged assault have been shared widely on social media this week.

Stephen E. Danish, the head of Immanuel Christian, said in an emailed statement that the school was cooperating with the police in the investigation:

“We take seriously the emotional and physical well-being of all our students, and have a zero-tolerance policy for any kind of bullying or abuse. We are deeply disturbed by the allegations being made, and are in communication with the young lady and her family to gather information and provide whatever support we can. All of the students involved in this matter have stepped away from school while the Fairfax County Police Department conducts an investigation.”

NBC also interviewed the girl’s family, including Cynthia Allen, her grandmother, who said the boys had told Amari she was “ugly” and her hair was “nappy.”

Telephone calls and messages left for Allen were not immediately returned Friday.

The Allens have met with school administrators and declined to send Amari back for classes until Monday.

Amari told WUSA9 that she had been afraid to report what had happened right away, and also that she had been bullied previously. The station reported that Allen had asked Amari about her hair Wednesday when she noticed it was uneven and had been chopped in some areas. “I want to see them dismissed from the school,” she said.

Immanuel Christian School is a private Christian school that enrolls kindergartners through eighth graders at its campus in Springfield, which is 15 miles southwest of Washington. Karen Pence, the wife of Vice President Mike Pence, accepted a part-time art teaching position there in January.

Immanuel Christian’s website — which describes the school’s expectations of students, parents and guardians, and its employees — says that it does not accept gay students and that it requires employees to affirm that marriage should be between only one man and one woman.