VICTORVILLE, Calif. (AP) — A viral video shows a Southern California sheriff’s deputy slamming a teenage girl to the ground during a fight outside a Friday night high school football game, a use of force her mother says sent the 16-year-old to the hospital with injuries to her head and spine.

The altercation prompted a protest Sunday at the San Bernardino County sheriff’s substation in Victorville, about 65 miles (105 kilometers) northeast of downtown Los Angeles.

The video, recorded on a bystander’s cellphone, shows the 16-year-old girl at first struggling with one San Bernardino County sheriff’s deputy. Another approaches her from behind and grabs her around her torso. That deputy lifts her up off the ground and slams her backwards to the pavement. The footage shows the teen’s head and back hitting the ground hard as her legs fly up into the air.

The department’s news release said the deputy “pulled the female away causing her to land on the ground.”

The sheriff’s department provided few details about the brawl outside the game. The news release said deputies responded shortly before 6:30 p.m. and found “multiple parties” fighting.

The department alleges the teenager grabbed another deputy’s pepper-ball launcher before the altercation. That deputy had sprayed pepper balls into the crowd to try to get people to disperse, “but the effort was ineffective, and the parties began moving toward the deputy,” the agency said in the news release.

The girl’s mother said the teenager was hospitalized with traumatic injuries to her head and spine.

“He attacked my daughter from behind,” Priscilla Jeffers told KCAL. “She’s 16 years old. He was a grown man, and he attacked my daughter. Now my daughter is scarred, now she’s messed up, and I don’t know how long she’s gonna be messed up because of this.”

The deputy’s actions are under investigation — which is the agency’s policy for any use of force — and his name has not been made public. The department said no deputies have been suspended or disciplined.

Priscilla Jeffers did not immediately respond to The Associated Press’ request for comment Monday.

The San Bernardino County District Attorney’s Office said Monday that it was aware of the incident but was not involved in a use of force investigation.

A 16-year-old boy was taken into custody after he allegedly punched a deputy in the face during the brawl, the sheriff’s department said. While the agency said he was booked into a juvenile facility, the teen’s mother said she was initially unable to locate him.

“He attacked my son first,” Kelani Lynch, the boy’s mother, told KTLA. “He was in the wrong and used aggressive force on a 16-year-old.”

Lynch also did not immediately return the AP’s request for comment.

Carl Coles, superintendent of the Victor Valley Union High School District, said officials are examining what occurred during Friday’s “distressing events.”

“We are fully cooperating with the San Bernardino County Sheriff’s Department in their investigation,” Coles said in a statement. “We have contacted the family to offer support to the student who suffered injuries. We request the community’s patience as this matter is still under investigation.”