Durham Regional police say officers who punched a prone 16-year-old during an arrest in Whitby, Ont., were following protocol.
Video posted on social media shows an officer pinning the teen down with his knee and punching him in the back several times.
Officers are heard yelling at the youth to move his hands back so they can handcuff him, as the person taking the video yells at police.
Police say officers were dispatched to a call about a distraught person possibly armed with a knife around 3:30 p.m. on May 15.
They allege the teen was not co-operative, so the officers tried to arrest him, took him to the ground, and one officer punched him to gain compliance.
Police say the teen was not injured and the video, along with the use-of-force report, will be sent to the professional standards unit for review.