Windsor police constable Kent Rice has been found guilty of assault.
Rice was accused of assaulting Gladson Chinyangwa last February in the stairwell of a housing complex.
Video shows Rice hitting Chinyangwa and then kicking him, twice, while on the ground.
Justice Donald Downie called the video "its own tie-breaker."
Downie said he could accept that Rice did not assault Chinyangwa when he pushed him to the ground and hit him. But the assault happened when Rice kicked Chinyangwa, who was on his back, on the ground.
Downie said he believed Rice when he testified that he felt threatened by Chinyangwa when he pushed him and that Chinyangwa was preparing to spit on Rice.
However, Downie said Rice used "excessive force" when he kicked Chinyangwa.
Downie wants to have the sentencing for Rice as soon as possible. He said taxpayers have been paying his full salary since he was suspended last year after the incident came to light in the spring.
Rice will be sentenced Sept. 24 at 10 a.m.