Pursuit of the Saitama Dog-Lover Disappearances

The pursuit of the Saitama dog-lover disappearances began with a missing-company-president report and reopened a forgotten series of disappearances linked to dog breeder Gen Sekine. It became a homicide investigation built on a narrow clue, a changing account of who had helped Sekine, and evidence recovered at a site in Gunma Prefecture. The case was ultimately closed with convictions for four murders, but the investigation never established how many people had really been killed.

A cold case returns

According to information passed through a police source, Sekine had been suspected of serial killing. His relationship to organized crime was described uncertainly: he was a yakuza, an ex-yakuza, or an affiliate. Several people associated with him had disappeared over the preceding decade. The Saitama police had investigated after the first three vanished, but the leads dried up and the case was forgotten.

The disappearance of Akio Kawasaki brought that history back into view. Kawasaki, president of a waste-management company, failed to return home. After several days, his wife reported him missing. At first, officers asked routine questions about his behavior, his home life, and whether he had enemies. Her answers gave them no obvious lead. Then she mentioned that Kawasaki had argued with a dog breeder. The officer’s response changed sharply: he warned her to prepare for the worst if her husband had been involved with Sekine. The police brought the old case back into active consideration.

Two months after Kawasaki disappeared, the Saitama police homicide division formed a special task force. Ten detectives were working on the case when a police source brought the information to Nakajima. The source told him there was no need to rush the story into print: if the Yomiuri waited, it could receive an exclusive. Even senior police officials did not yet know the case’s details, making a leak to competing papers seem unlikely.

Reporting and the expanding field of suspicion

The Yomiuri team’s work was kept secret, and Jake Adelstein was assigned to search newspaper archives for references to Sekine or his pet shop, African Kennel. The newspaper had no electronic archive of past editions, so the search meant leafing through old scrapbooks. After two days, he found a July 14, 1992, report about a Kumagaya pet breeder who had kept a lion on his balcony; the animal was to be sent to a zoo in Gunma Prefecture. The article gave the investigation a concrete piece of Sekine’s past, but it did not explain the disappearances or provide a motive.

By the end of January, work led by Nakajima had connected four missing people believed to have been killed by Sekine: Kawasaki, a housewife, a yakuza boss, and the boss’s driver. The team still could not identify why they had disappeared. Its plan was to hold publication until shortly before the breeder’s expected arrest. That careful timing did not secure the scoop, and the account later presents Adelstein’s failure to stay close to the case as a decisive reporting mistake.

The police investigation also reflected a procedural calculation. A warrant for fraud was easier to obtain than one for a violent crime such as homicide. The homicide detectives could use an arrest on the lesser charge to question a suspect about other matters, including murder. The account describes this as standard practice for the homicide unit. The distinction mattered: fraud became a possible route into an investigation whose central suspicions concerned killings, even though the case’s motives and the full extent of the crimes remained unsettled.

Testimony redirects the investigation

Sekiguchi argued that the evidence concerning Yasunobu Endo was the strongest basis for charging Sekine with murder from the outset. He believed Sekine would confess quickly, but said that his recommendation carried little weight because he was not part of the elite homicide unit. The available support was circumstantial and based partly on hearsay: witnesses could place Endo with Sekine shortly before Endo vanished and could say that Sekine had injured him that day. Sekiguchi estimated that Sekine had killed eight people, but that was an investigative assessment, not the eventual number established in court.

The investigation’s direction changed when Arai began talking. Arai disclosed that he had not participated in the disappearances of the last four victims; his driver, Shima, had. Arai had learned from Shima that Sekine killed Endo and Wakui, Endo’s driver, with poison, and that Shima helped bury them. Shima’s knowledge, rather than Arai’s account alone, now appeared capable of providing a case against Sekine.

The police arrested Arai on a fraud charge, hoping to learn more about Shima. They did not expect him to be useful in proving his wife’s decade-old murder, which would be difficult without a body. But Takada learned that tapes existed and immediately contacted Shima, demanding that he disclose where Endo’s body was buried. The investigation then reached another impasse: without Shima, there would be no interrogation and no case. In November, Sekiguchi left the team and returned to the Anti–Organized Crime Division. The unspoken assumption was that Shima had been killed and the case would remain unsolved.

Recovery, arrests, and the missed scoop

Takada continued searching for Shima. In late November, he found him; Shima had changed his name and married. Takada passed the information to Sekiguchi, who reported it to the Saitama police. They arrested Shima in December. Confronted with the existence of the tapes, Shima gave information that led police to a site in Gunma Prefecture. There, investigators found enough of Kawasaki’s teeth to build their case. The search was conducted by a very small team, without the Yomiuri or anyone else knowing about it.

On January 5, just after the New Year’s holidays, the Saitama police released Shima on bail and announced the arrest of Sekine and his wife, Hiroko, for Kawasaki’s dismemberment. Sekine admitted almost everything within hours. After an investigation that had lasted an agonizing year—and traced disappearances reaching back more than a decade—the Saitama Dog Lover Serial Disappearances case was declared closed.

The closure did not bring the newspaper the exclusive. Adelstein later concluded that he had missed a chance to learn that police had found Kawasaki’s remains: he had not visited Sekiguchi over the holidays, had failed to keep tabs on the open case, and had never given Sekiguchi his home phone number. Sekiguchi had called the office despite the risk, but Adelstein was not positioned to receive the information in time. The failed scoop gives the ending a second measure of consequence: the investigation succeeded, while the reporter who had followed it closely lost the story at its decisive turn.

What the verdict left unresolved

Sekine and Hiroko were convicted of murdering only four people. The number was not presented as a complete accounting of the suspected crimes. The investigation had considered more disappearances, and Sekiguchi had estimated eight victims, but the final convictions did not settle that larger question. The case therefore ends with a legal conclusion and an enduring uncertainty: four murders were proved in court, while how many people Sekine and his associates had actually killed remained a mystery.