Adachi alleged that San Francisco sheriff's deputy Scott Neu, who was accused in 2006 of forcing inmates to perform sex acts on him, forced the inmates to fight twice. The 2006 case was settled out of court.
Both inmates were injured in the bouts but were threatened not to seek medical treatment.
"Deputy Neu forced these young men to participate in gladiator-style fights for his own sadistic entertainment," Adachi said in a statement.
The San Francisco Deputy Sheriff's Association told the San Francisco Chronicle that the allegations were "exaggerated" and the fighting was "little more than horseplay."