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A California police department is investigating a violent arrest last week of an autistic teenager by an officer responding to a report of a stabbing.

A home security video camera recorded images as the teen was thrown to the ground and punched in the face Wednesday in Vacaville, about 50 miles (80 kilometers) northeast of San Francisco.

Acting Vacaville Police Chief Ian Schmutzler said in a Facebook statement Friday that concerns about how the arrest was handled were justified and the police department leadership was taking them seriously.

The teen, Preston Wolf, was being picked on and got a metal object to defend himself in the altercation that led to police being called, his father, Adam, told CBS13 Sacramento. That altercation was broken up before police arrived.

The camera recorded the officer approach as Preston stood on a sidewalk with a scooter. The youth sat down and then jumped up as if to run away. The officer caught him, threw him down and punched him during a struggle.

Schmutzler said investigators are examining “the initial call of someone actively ‘being stabbed’ to the descriptions provided by witnesses, the knowledge of a pipe or knife being involved, as well as the officer’s response, communication with other officers who were at the original scene, and all of the other questions that need answering.”

Investigators were also reviewing police dispatch recordings, body-worn camera video, the door camera video and other visual or audio evidence, he said.

Schmutzler said many people have asked whether the arresting officer knew that the youth had special needs.

“In the dispatch audio, there is a conversation between a dispatcher and a different officer (who was not on the scene) who asked whether the suspect was ‘Preston.’ Our preliminary review of the available video and radio traffic indicates the arresting officer did not have prior knowledge that the suspect was an individual with special needs,” the chief wrote.

He said the time stamps of the various sources were being confirmed to develop an accurate timeline.