The town of Erick is looking for a new police chief following the chief's arrest on assault and battery charges.
Mike Day resigned last week. Day is accused of assaulting a shackled inmate at the Beckham County Detention Center in December of 2013.
According to court documents, Day arrested Arturo Gonzales and Mark Watson, then Watson and Day exchanged words at the detention center.
Surveillance video showed Day walk over to Watson, Watson stood up and Beckham County Sheriff Scott Jay said that is when Day assaulted the restrained inmate.
"It looks like he punched him in the gut," Sheriff Jay said.
Court documents state you can hear Watson on the video yell to Beckham County staff, "Are you going to let them do this to me?"
"I just couldn't believe it and you know, I hadn't had anything like that happen so outwardly in front of other people," Sheriff Jay said.
The sheriff said Watson's hands remain at his waist the whole time, and he does not see any aggressive action from Watson.
"That is not a practice that any police officer should take with any prisoner who is in custody," Sheriff Jay said.
The arrest affidavit said four jail staffers saw Day either strike or push Watson. One deputy reported that Watson said, "I know where you live," just before the alleged assault.
"This circumstance though, I'm going to have to explore some policies and some other things when it comes to other agencies housing at my facility," Sheriff Jay added.
According to court documents, Day said Watson had threatened his officer's life and his life.
Court papers also said Day denied striking Watson and said he only helped Watson sit back down.
At the request of the Beckham County District Attorney, the OSBI said it is also investigating Mike Day for official misconduct over allegations that he entered a home without a warrant.
Day bonded out of jail the same day he was booked.