A 45-year-old man serving an indefinite prison sentence for the 2004 murder of a girl in Tsuyama, Okayama Prefecture, has suggested that he was involved in the 2007 murder of another girl in Kakogawa, Hyogo Prefecture, east of Okayama, investigative sources said Wednesday.

The inmate has also hinted at his involvement in the 2006 stabbing of a girl in Tatsuno, Hyogo Prefecture, according to the sources. The girl was seriously injured.

Hyogo Prefectural Police plan to arrest the man soon on suspicion of attempted murder in the 2006 case.

While in prison in 2018 for a different attempted murder case, the man was arrested and indicted for the 2004 case, in which he intruded into a house in Tsuyama, strangled a girl in the third grade of elementary school and stabbed her several times to death. His indefinite sentence was finalized in September 2023 as the Supreme Court dismissed the defense side's appeal.

Meanwhile, police continue investigating the 2006 and 2007 cases.

In the 2006 case, a fourth-grade elementary school student was stabbed with a knife and seriously injured on her way home from a private tutoring school.

In the 2007 case, second grader Yuzuki Unose was stabbed in the left chest to death in front of her home.