What to do when your son is beaten by correctional officers in a jail setting?

my son filed a grievance and the CO's got upset. He was taken to a secluded area in the jail while the officers used an excuse that they were holding a DR hearing on him for an earlier incident. The lied to him saying that I, his mother called and told them that he stated that he was choked by a CO. They beat him up, kicked him in his back several times, one of the CO's physically opened his eye lids with his hand and sprayed him in the eyes at close range with mace. Then they wrote up in the DR reports that he was belligerent, cursing them out, threatening them and their mother and jail staff. They fabricated the entire incident. I requested an emergency visit with my son and he was so broken in spirit and had physical bruises.