A man serving a life sentence for killing a girl in western Japan two decades ago was arrested on Thursday for an alleged stabbing in 2006, while hinting at his involvement in the high-profile murder of a different girl the following year.

The arrest of Kunihiko Katsuta, 45, potentially signals a new phase in the investigation over the fatal stabbing of 7-year-old Yuzuki Unose, in Kakogawa, Hyogo Prefecture, in 2007, which local police have been unable to solve.

Katsuta was handed an indefinite prison term by the Okayama District Court in 2022 for stabbing 9-year-old Yukiko Tsutsushio to death in Tsuyama, Okayama Prefecture neighboring Hyogo in 2004.

His possible involvement in other attacks targeting girls, including the 2007 case, emerged as investigators continued questioning him while he was behind bars, according to investigative sources.

On Thursday, Katsuta was arrested for allegedly attempting to kill a girl, a fourth grader in elementary school, in 2006 by stabbing her in the chest on a street in Tatsuno, Hyogo Prefecture.

She was attacked on her way home from a cram school and security camera footage near the site showed a man carrying a backpack fleeing the scene, according to the sources.

In the 2007 case, Yuzuki, a second-grade elementary school pupil, was stabbed in her chest and stomach in front of her house after returning from a nearby park.

At the time of his arrest in the Tsuyama case in 2018, Katsuta was already serving time for stabbing a female junior high school student in Himeji, Hyogo Prefecture, in 2015. He had also previously faced allegations of random attacks on other girls in the same prefecture.