NAGANO -- Over 300 tips were provided by the public to a police hotline set up following a fatal stabbing spree in front of JR Nagano Station, playing a crucial role in the arrest of the suspect behind the case, police said.

Yusuke Yaguchi, 46, a resident of the city of Nagano, was arrested Jan. 26 on suspicion of attempted murder in connection with the Jan. 22 attack that left one dead and two others injured.

Masato Yoshiike, head of Nagano Prefectural Police's first investigation division, revealed at a press conference on Jan. 26 that analysis of footage from security cameras contributed most to identifying the suspect. "The 'relay investigation' played a crucial role. We also received a lot of information (from the public), and we are truly grateful," he told the press, referring to an investigation method of retracing the suspect's whereabouts using footage from security cameras and other sources.

According to those close to the case, based on security camera footage and witness information the suspect was initially believed to have fled to the west of Nagano Station following the attack. However, he could not be tracked down beyond the station area, prompting the prefectural police to collect security camera footage from broader areas for analysis.

The police also released images of the suspect twice after the assault. The second image was provided by a user of the station and showed a clearer profile of the suspect. The Nagano police hotline had since been flooded with calls from people offering information such as, "I saw a person resembling him," and, "He looks like an acquaintance." By Jan. 25, the day before Yaguchi's arrest, the hotline had received 326 tips.

Utilizing those tips, the prefectural police linked security camera footage from different spots and narrowed down the neighborhood where the suspect resided, about 3 kilometers east of Nagano Station.

In Japanese police investigations, image data has increasingly been utilized in line with the widespread use of security cameras and dashcams, as well as the sophistication of smartphone cameras. For the December 2024 attack in Kitakyushu that left a third-year junior high school student dead and another student injured at a fast-food restaurant, the "relay investigation" tactics played a key part in the arrest of the suspect.

(Japanese original by Hideyo Suzuki, Nagano Bureau)