Being a police officer is a hard, thankless job, and the vast majority of cops are good people. Then there's Phoenix police Officer Patrick Larrison, who ruins the public perception of police officers when he essentially body-slams an unarmed, non-threatening 15-year-old girl into the side of a building.

It was all caught on film, which should make it pretty tough for the officer to claim the girl was "resisting."

In January, Larrison responded to a call about a fight between the 15-year-old and her mother in the parking lot of the Ombudsman Charter School near 40th Street and Thomas Road.

The girl was drinking in school and had become belligerent before assaulting a teacher. Her mother called police and showed up at the school where the two got into a physical altercation in the parking lot, and the mother apparently tried to restrain the girl until police arrived.

When police showed up, the girl started to walk -- slowly -- away from the officers.

Larrison, seemingly unprovoked, charges the girl, slams her into the side of the building, knocking her off her feet.

Check it out below.

As you can see in the video, the girl's a punk -- but that's no excuse for Larrison to be a bully just because he's got a badge.

The video was uploaded to Youtube on March 20, and first seen by authorities within the Phoenix Police Department Tuesday night after a department employee saw it and told a supervisor.

Larrison, a six-year veteran, has been placed on administrative leave as the department investigates whether he used an "unlawful use of force" in detaining the girl.