A sheriff’s deputy assigned to a public school in Florida was charged Tuesday with child abuse after school surveillance footage showed him grabbing a 15-year-old student by the neck and slamming her to the ground, the authorities said.

The video of the Sept. 25 encounter at Cross Creek School in Pompano Beach, Fla., starts with the student, whose name was not released, and the deputy, Willard Miller of the Broward County Sheriff’s Office, standing in a room together. Two other people are sitting on chairs. The teenager walks up behind the deputy and pokes him in the back of the knee with her foot while he is looking at his phone.

For about a minute, Deputy Miller, 38, can be seen talking to the girl before he lunges toward her, grabs her neck, throws her to the ground on her back, flips her over onto her stomach and pins her down while holding her wrists together.