Kyodo News

Three people were found dead in a possible murder-suicide at home in Tokyo's Adachi Ward on Monday afternoon, while a 15-year-old boy found at the scene with his hands cut off at the wrist and the back of his head caved in has fallen into a coma after being rushed to a hospital, police said.

The three are believed to be Toru Sasaki, 52, his wife Kazuko, 49, and Sasaki's mother Tokuko, 84, while the boy is Sasaki's son, who is a first-year student in high school, the police said.

All were found bleeding, and a bloodstained ax was discovered in the house, according to the police.

The boy was quoted as telling the police before he lost consciousness, "My father did it to me," while a note with blood, believed to have been written by Sasaki, was found in the house, which suggested he would commit murder-suicide. The police said they suspect that he aimed to kill his family.

The police believe the ax to be the murder weapon, they said.

The boy's 18-year-old brother was not at home at the time of the incident. A passersby found blood draining from a shutter of the house and informed police.

Sasaki was involved in a business that involves repairing and selling used machines, according to his neighbors.