On Jan. 26, 1948, a man claiming to be a public health official walked into a branch of Teikoku Ginko (Imperial Bank) in Tokyo's Shiinamachi district and told 16 clerks and customers dysentery had broken out in the neighborhood.

He told them to drink a liquid he claimed was a remedy. The liquid, however, was actually poison.

Twelve of the 16 people died, and the murderer escaped from the bank with cash and checks.

Seven months later, Sadamichi Hirasawa, then a famous painter, was arrested as a suspect. A health ministry official whose business card was presented by the perpetrator of a similar poisoning attempt told police Hirasawa was among those to whom he had given his card.

He was tried, found guilty and sentenced to death. The Supreme Court upheld the sentence in 1955, mainly on the basis of a written confession Hirasawa later retracted. He continued to maintain his innocence until he died in prison in 1987.