The suspect's mother and another woman were injured.

The Hyogo prefectural police department is investigating the incident as a murder case.

Following an emergency call for help at around 6:20 a.m. (9:20 p.m. Saturday GMT), police officers found Tatsuo Nanbu, 83, and his 83-year-old wife, Miyuki, lying bleeding at their house and they were subsequently confirmed dead.

He was stabbed in the neck and chest, while his wife had stab wounds around the back, according to investigative sources. The suspect's 52-year-old mother, Tomoko Takeshima, fractured her arms.

Yaeko Tsuji, a 79-year-old neighbor, was found dead with a stab wound near the neck. Another woman, 65, was injured but her injuries are not life-threatening, the sources said.

The police discovered the suspect, Kanami Takeshima, at a nearby shrine and arrested him on charges of possessing a knife and a metal baseball bat in violation of the firearms and swords control law. His clothes and the knife had bloodstains.

The unemployed man admitted the charges, telling the police that he was intending to stab anyone with a knife used at his home, according to the sources.

The police plan to investigate any links he may have with the attacks on the five people, the sources said.

His mother told the police officers who arrived at her house that her son is responsible for the rampage.

The suspect was living with her and the slain grandparents. The mother told the police that the family members were not on good terms. (Jiji Press)