Two Nagoya Prison guards were charged Thursday with taking part in the fatal assault of a male inmate in 2001.
Indicted were Hiromasa Okamoto, 47, a deputy chief guard, and Masahiro Takami, 43, a director of a guard division, according to the Nagoya District Public Prosecutor's Office.
They are accused of assisting Mikio Otomaru, 46, when he aimed water from a high-pressure fire hose at the inmate's bare buttocks in a cell at around 2:20 p.m. Dec. 14, 2001, as punishment.
Okamoto and Takami put the 43-year-old inmate on his stomach and removed his trousers, prosecutors said.
As a result of the assault, the inmate suffered serious injuries to his rectum and anus, and died of an infection the next afternoon, it said.
Okamoto was earlier indicted for allegedly inflicting serious injuries on another inmate in September, and is now on trial for that charge. Takami was indicted for the first time.
Two other guards were also present during Otomaru's alleged assault, but prosecutors decided not to press charges against them, the office said.
Otomaru has denied assaulting the prisoner, claiming the hose was used to wash the inmate and not for punishment, according to the office.
Eight guards have been indicted in connection with assaults of inmates at the prison.