The 16-year-old girlfriend of an 18-year-old university student suspected of killing his mother and injuring his father and brother said they had planned to die together after killing all their family members, police said Sunday.
"We had thought to die together after killing members of our families and spending some time all by ourselves," the police quoted the high school student, who along with the suspect cannot be identified because they are minors, as saying.
The university student was arrested Saturday on suspicion of stabbing his 43-year-old mother to death and seriously injuring his 46-year-old father and 14-year-old brother at their home in Kawachinagano, Osaka Prefecture, earlier that day.
The suspect has allegedly told the police he was fed up with living but was afraid to die alone, so he bought a kitchen knife and tried to kill his family.
The girl, who was with the suspect when police officers located him fleeing in a car some 2 km from his home shortly after the incident, was arrested later Saturday on suspicion of preparing for murder by buying a separate kitchen knife to kill her family members.