The Teigin Bank Poisoning and Sadamichi Hirasawa’s Contested Conviction

A visitor claiming to protect the bank from an epidemic

The crime occurred at the Shiinamachi branch of Teikoku Bank — commonly shortened in later accounts to the “Teigin Incident.” A man arrived after the branch had closed and presented himself as a public-health official. He claimed that an infectious-disease emergency required the people inside to take preventive medicine immediately.

Sixteen employees, customers or family members were persuaded to drink the liquid. Twelve died. Four survived. While the victims were incapacitated, the intruder took cash and checks and left. The method was unusually controlled: the killer did not simply contaminate food or drink and disappear. He stood in front of the group, presented himself as an authority figure and directed them through the act of swallowing the poison.

The investigation turns to Sadamichi Hirasawa

Police mounted a large investigation and arrested painter Sadamichi Hirasawa later in 1948. Several pieces of circumstantial evidence were used against him. Contemporary and retrospective accounts noted that he had possessed a calling card connected to a name used by the perpetrator, that handwriting evidence was said to link him to a stolen check, and that investigators questioned unexplained money in his possession.

Hirasawa confessed during interrogation, but later withdrew the confession and said it had been obtained through coercive questioning. He went to trial maintaining his innocence. The court convicted him and sentenced him to death. Japan’s Supreme Court upheld the conviction and sentence in 1955.

A death sentence that was never carried out

Hirasawa remained under sentence of death for more than three decades. Justice ministers repeatedly declined to authorize his execution. He continued to insist that he had not committed the Teigin murders and pursued retrial and clemency efforts from prison.

He died of pneumonia in a prison hospital on May 10, 1987, at age 95. His death ended the possibility of executing the sentence but not the legal and historical dispute. His lawyers and supporters continued to seek a posthumous retrial intended to clear his name.

Why the conviction remained controversial

The conviction was not erased: it was upheld through Japan’s court system and repeated retrial applications were rejected. But substantial controversy persisted around the reliability of the confession, the circumstantial nature of important parts of the prosecution case and questions about the perpetrator’s apparent knowledge of poisoning technique.

Hirasawa’s supporters argued that investigators should have pursued people with specialized military toxicology experience more aggressively. Later historical research explored possible connections to former wartime chemical or biological-warfare personnel. Those theories are important to the history of the case, but they are not proven identifications of the bank killer. This page therefore does not name a Unit 731 member, former soldier or any other alternative suspect as the true perpetrator.

Repeated attempts to reopen the case

By January 2004, lawyers were concluding what was described as the 19th campaign seeking a retrial. The Japan Times reported that the previous 18 efforts had been rejected for insufficient grounds to reopen the case. The legal campaign continued after Hirasawa’s death.

On November 24, 2015, attorneys acting for Hirasawa’s descendants filed a 20th retrial petition. The existence of repeated petitions does not itself establish innocence, just as the old conviction does not eliminate the documented controversy surrounding it. As of the sources reviewed for this dossier, no posthumous acquittal has displaced the conviction.

Timeline

1. January 26, 1948: A man posing as a health official administers poison to 16 people at the Shiinamachi branch of Teikoku Bank in Tokyo. Twelve die and money is stolen.
2. August 1948: Sadamichi Hirasawa is arrested during the investigation.
3. After arrest: Hirasawa confesses during interrogation, then recants and alleges coercion.
4. 1955: Japan’s Supreme Court upholds his conviction and death sentence.
5. May 10, 1987: Hirasawa dies of pneumonia in a prison hospital at age 95 without having been executed.
6. January 2004: Lawyers conclude a 19th retrial campaign; the preceding 18 efforts had been rejected.
7. November 24, 2015: Attorneys for Hirasawa’s descendants file a 20th petition seeking a retrial.

The victims

Twelve people died after being deceived into drinking the poisonous liquid. Four others survived. The victims were not participants in a confrontation or criminal transaction; they followed what appeared to be an urgent public-health instruction delivered by a man presenting himself as an official. This dossier avoids graphic descriptions of their deaths and treats the poisoning as one single criminal event rather than fragmenting the twelve deaths into separate pages.

Current status and the unanswered question

Legally, Hirasawa was convicted and that conviction survived his lifetime. Historically and evidentially, however, the case remains contested. Because there has been no posthumous acquittal but also no generally accepted resolution of the doubts that drove decades of retrial litigation, Crime by Region classifies this dossier as unsolved / partial — contested conviction.

The central unanswered question is straightforward: was Hirasawa the man who entered the bank on January 26, 1948? Courts said yes; Hirasawa, his supporters and generations of advocates said no. Later alternative-perpetrator theories have not produced a judicially established replacement offender.