A member of the Franklin County Sheriff's Office is under investigation following allegations that he assaulted a suspect while they were in custody.Vermont State Police are investigating Capt. John Grismore after he was placed on administrative leave. Patrol deputies reported that he mistreated a suspect who was in custody and being held at the Franklin County Sheriff's Office on Sunday.A video of the incident provided by the Franklin County Sheriff's Office shows the suspect handcuffed and shackled to a bench before falling down and hitting his face. After two deputies help the man into a sitting position, the suspect attempts to stand again when Grismore enters the frame and kicks the man in the crotch and abdomen area several times.Grismore was running unopposed for the GOP nomination for Franklin County Sheriff in Tuesday night's primary election.Franklin County Sheriff Roger Langevin referred the case to the Franklin County State's Attorney's Office, which then subsequently requested a criminal investigation from Vermont State Police.Former Vermont U.S. Attorney Jerry O'Neill watched the video and said this situation appears "black and white" to him."I doubt that officer will ever again work in law enforcement," O'Neill said. "You cannot treat someone like that. This is man who is cuffed, he is in custody. There's no excuse for it."No further information is available at this time. NBC5 will update this story when we learn more details.