Police in Japan have arrested a 45-year-old man on suspicion of stabbing an elementary school girl in western Japan’s Hyogo prefecture 18 years ago.

Katsuta Kunihiko is already serving a life sentence for murdering another elementary school girl in Okayama Prefecture in September 2004. His sentence ended last year.

Investigation sources say he is a suspect in the attempted murder of a fourth-grade girl in Tatsuno City in September 2006. The girl was on her way home from cram school and suffered serious injuries.

The case remained unsolved due to lack of witnesses and evidence.

As the method of the attack is similar to that of the Okayama case, Katsuta was voluntarily interrogated and reportedly admitted his involvement in the attack on Tatsuno City. Sources say what he told police is consistent with the girl’s injuries and the circumstances surrounding the incident.

Katsuta had also reportedly admitted involvement in the fatal stabbing of a 7-year-old girl, Unose Yuzuki, in the city of Kakogawa, also in Hyogo, in 2007.

Police plan to question Katsuta further to uncover details of the two unsolved cases.