BBC NewsUS prosecutors have released video footage of a sheriff's deputy striking a 15-year-old girl and throwing her onto a cell floor.
The video is evidence in the case against Washington state Deputy Paul Schene, accused of using excessive force against the girl in November.
The incident began after the girl was arrested in a car theft inquiry.
Footage shows the deputy lunge at the girl after she kicks one of her shoes towards him at SeaTac City Hall.
"We believe this case is beyond just police misconduct, it's criminal misconduct," King County Prosecutor Daniel Satterberg said.
"This is clearly excessive force."
Mr Schene, 31, pleaded not guilty to fourth-degree assault on Thursday.
The second officer shown in the video was a trainee at the time and is not under investigation.
The Associated Press news agency said that according to court documents, the girl complained of breathing problems after the incident and medics were called to check her.
Mr Schene's lawyers had asked the judge not to release the video, arguing that it would inflame public opinion and prejudice the deputy's right to a fair trial.
I'm surprised this hasn't been posted here yet.
This asshole is fucking finished, and good riddance. I can't even comprehend how stupid this deputy is.
Though I'm glad to hear that the recruit won't be facing an investigation. He probably should have done something to stop it, but new guys can be like deer in headlights when something big like this goes down. Initially, I thought he was going to lose his job as well.
Also, I want to point out that this happened back in November of 2008, and unless I'm missing something the public was made aware of this in February. This is just an assault investigation, and it took roughly three months before anything was released. Now imagine how long an investigation takes for police brutality that involved the use of dangerous weapons. I bring this up because in past threads some members here seemed to think an investigation into police brutality should be resolved in a matter of weeks.