The family of a Nagoya Prison inmate who died at the prison in 2001 filed a lawsuit targeting the government Friday, claiming assaults by guards had caused his death and seeking 88 million yen in compensation.
According to the complaint, filed at the Kyoto District Court, the guards in November 2001 began spraying the inmate, 43, in the rectum with water from a fire hose.
The man was allegedly being disciplined for misbehavior, such as messing up his cell.
The inmate died on Dec. 15 that year as a result of his rectal wounds.
In a comment released Friday, the plaintiffs said the guards had engaged in acts of "cruel torture."
The Correction Bureau of the Justice Ministry, in charge of managing prisons, refused to make any detailed comments on the matter.
Three guards have been tried in connection with this case, with prosecutors alleging they abused their positions as special public officers and caused the inmate's death.
The guards have pleaded not guilty, claiming their actions were not meant to punish the inmate but to clean him.