An 86-year-old woman in Zama, Kanagawa Prefecture, was arrested Saturday for allegedly killing her 90-year-old husband, police said.
Shiro Yagi was found dead at 10 a.m. by the police after the couple's second daughter phoned emergency workers.
The body had stab wounds to the chest and other areas.
Yagi's wife, Tsuruno, was sitting beside the body and was arrested, the police said.
She was quoted as saying, "I could not communicate with my husband who had hearing difficulties and we had constant fights. I killed him because he sometimes beat me."
According to police, she allegedly used a sharp object to stab him several times in their living room at around 4 a.m. and then killed him by suffocating him with a plastic bag.