Miyagi Prefectural Police

Miyagi Prefectural Police is the regional law-enforcement body enlisted to help investigators trace the background of Shunichi Watabe, the identity used by Mutsuo Koshikawa. Its contribution represents an attempted bridge between the Tokyo murder investigation and Watabe’s earlier life in Miyagi; at the point described, the request has produced no leads.

Role in the Investigation

After investigators identified the burned body found by the Shinkoiwa riverbank as Mutsuo Koshikawa, they established that Koshikawa had previously lived under the name Shunichi Watabe. Watabe had also been in a long-term relationship with Kyoichiro Kaga’s mother. Although the discovery clarified the identity behind the assumed name, investigators still lacked the connection between the murders of Michiko Oshitani and Koshikawa. They therefore made an official request to Miyagi Prefectural Police for background information on the man known as Watabe.

Limits of the Inquiry

The request reflects the difficulty of reconstructing a life concealed behind conflicting identities. Koshikawa had lived in a Tokyo apartment for nine years without updating his residence-certificate details, and the Maebashi address given in his submitted documentation appeared to be false. Separately, fingerprint comparisons established that the man known as Watabe in Sendai was the same person as Koshikawa. These findings helped investigators connect identities across places, but did not by themselves explain Watabe’s past or establish how the two murders were related.

The account records that the Miyagi inquiry had yielded no leads by the time the task force reviewed its progress. The organization’s role is thus presented as an important investigative channel, but not a source of an immediate solution: the police had to continue testing the connections through other evidence and lines of reasoning.