Mie Prison in Tsu, Mie Prefecture, has filed a criminal complaint with public prosecutors against its chief guard, accusing him of assaulting 13 inmates, prison officials said Sunday.
The 44-year-old chief jailer has admitted to the violence and the prison plans to reprimand him soon, the officials said.
The jailer beat and kicked 13 prisoners on various occasions between August last year and March this year while they were working in the sewing workroom, saying they were disobedient, the officials said.
The prison filed the criminal complaint with the Mie District Public Prosecutor's Office on May 8. The prison officials said none of the prisoners was injured in the assaults.
The jailer has been transferred to the prison's mail division so that he will not come in contact with prisoners.
Prison Warden Akio Yamaguchi said, "It's quite regrettable. We will enforce education of the staff to prevent recurrence of such incidents."