Beaten while cuffed? That's low, even for a dirty cop's standards. Plus if there are witnesses it's tough to use the resisting arrest angle.
I was a spectator when the cops finally caught a guy who had been robbing pharmacies at gunpoint in the city. He was taken down while trying to get away from his latest robbery, from car to the ground, where he took several shots to the face, gave blood to the pavement via his mouth. Cop said "you like scaring old ladies" or "you like pointing guns at old ladies", something like that. That was the justification for the beating while he was pretty much subdued. THEN he was cuffed.