A 16-year-old high school student was arrested Saturday for allegedly killing his grandfather in their home in the city of Tahara, Aichi Prefecture. He has also hinted that he murdered his grandmother, as well.

The boy initially claimed that he only discovered the two bodies at his house — confirmed by police on Saturday as his grandparents, a 75-year-old resident and his 72-year-old wife, who both lived with him there — but he then later admitted to the allegation, according to investigators.

Autopsies found that the couple died of hemorrhagic shock. Both of them had numerous stab and slash wounds across their bodies.

The student is suspected of killing his grandfather in their home by stabbing him in the neck at around 2 a.m. on Friday.

According to police, when he returned home with his 53-year-old mother on Friday at around 4:35 p.m., he told her that he had discovered his grandparents collapsed and bleeding on the floor of a bedroom on the first floor, and then asked her to make an emergency call.

Later during the investigation, he confessed to police that he had killed them in the early hours of Friday. Police believe he had some troubles with his grandparents.

The suspect lived in the main building with his grandparents and his parents lived in another building on the premises.

Translated by The Japan Times