An officer is under investigation for using excessive force after a video surfaced of him pushing a teenage girl against a wall, knocking her to the ground.Phoenix Police Officer Patrick Larrison has been placed on administrative while the criminal and internal investigation is underway.The use-of-force case incident caught on tape. A Phoenix Police employee saw the video and told supervisors.Back in January, at Ombudsman Charter School, the 15-year-old girl was caught drinking at school. When her mom arrived, she and her mom got into a physical fight, and the police were called.She was apparently belligerent and walked away from officers. That's when Officer Larrison used an 'impact push' to stop her and handcuff her."That type of video is very concerning, we don't want that to be our image within the community, but unfortunately we have these things occur," says Sgt. Trent Crump."At face value all you see is the force, it certainly appears at this point it is outside of the boundaries considered to be reasonable... We have to get to the bottom of it."The girl was uninjured. Larrison has been a member of the force for 6 years.