Two guards at Nagoya Prison were served a second arrest warrant Wednesday for allegedly assaulting a male prisoner and causing his death in May, prosecutors said.
Deputy Chief Guard Akihiko Maeda, 40, and Hiroki Ozawa, 27, are suspected of attaching a restraining device which features leather handcuffs and a belt around the abdomen of the 49-year-old inmate for insubordination at 10 a.m. May 27, according to prosecutors.
The prosecutors said the prisoner complained of illness and died at around 8:30 p.m.
Also Wednesday, prosecutors indicted five Nagoya Prison officers, including Maeda and Ozawa, on charges of inflicting serious injuries on an inmate in September.
They were allegedly involved in putting a restraining device on a 30-year-old man for about an hour and a half Sept. 25, even though there was no possibility of violent behavior.
The indictment says the guards attached the device so tightly around the man's stomach that he bled internally and had to be hospitalized.
Sources close to the cases said Maeda played a major role in both incidents by binding the men with leather handcuffs and issuing orders to other guards.
The prisoner in the September incident had asked the Nagoya Bar Association in April to investigate his claims that prison officials had used leather manacles on him and punished him severely for trivial reasons.
Maeda questioned the prisoner about his claims Sept. 25 as well as several times prior to the day of the incident, according to investigative authorities.