The Tokyo High Court will drop the retrial plea for the late Sadamichi Hirasawa, who was condemned over the infamous 1948 "Teigin Incident" murder case, because his adopted son, who was pursuing the appeal, died in October.
Takehiko Hirasawa, who had filed the plea, the 19th, died in his Tokyo home at age 54.
A three-judge panel led by Hidenobu Konishi made the decision Monday.
A group of lawyers for Takehiko Hirasawa asked the high court in late November not to end the court procedures. They plan to file an appeal against the decision.
Sadamichi Hirasawa, a painter, was convicted of killing 12 people with poison at a branch in Toshima Ward, Tokyo, of Teikoku Ginko, or Teigin (Imperial Bank).
He died in a medical prison in May 1987 at age 95, in the middle of his 18th appeal for retrial. He maintained his innocence throughout his trial and his 39 years on death row.
Takehiko Hirasawa, the son of novelist Tetsuro Morikawa (1923-1982), became Sadamichi Hirasawa's adopted son in 1981 and filed the plea for a retrial in 1989. Tetsuro Morikawa served as secretary-general of a group of supporters for Sadamichi Hirasawa.
The group of lawyers had submitted new evidence, including an expert opinion on poison.
In the Teigin Incident, a man claiming to be a health official went to the Teigin branch and got the victims to take what he claimed was a preventive medicine against dysentery. It was poison and while they were dying he stole checks and cash.
Tokyo police arrested Sadamichi Hirasawa in August 1948, and his death sentence was finalized in 1955.
The Teigin Incident is one of Japan's most widely known postwar crimes.