Many Questions Unanswered : ‘Murderer’ Still on Death Row in Mysterious 1948 Japan Poisonings

A sensational poisoning in U.S.-occupied Japan, in which 12 bank employees died after drinking a homemade cyanide brew administered by a man posing as a health official, is one of the great mysteries in the annals of Japanese crime.

The drama is clouded by germ warfare experiments, war criminal suspects and charges of a U.S. cover-up.

William Triplett spent seven years researching a book on the case, “Flowering of the Bamboo,” in which he unravels a tangled web of crimes, accusations and cover-ups, and levels serious allegations about the conduct of the U.S. Army in postwar Japan. He still finds many questions unanswered.

Shown on U.S. TV

American and foreign journalists have recently written about the case, and ABC-TV’s program “20-20” showed a segment on it last year.

“I believe the U.S. Army has a great number of records that would shed still more light on the case--and possibly solve it--but it’s getting more difficult to get them because of the current publicity,” Triplett said.

“The fact that documents are still being withheld from journalists investigating the case tells me this story is not over.”

THE CRIME: A Japanese man dressed as a uniformed health official appears at the Imperial Bank in downtown Tokyo just after closing time in January, 1948, while workers are counting the day’s receipts.

After invoking the name of an American occupation officer, he explains that a customer of the bank has contracted dysentery and that he is there to dispense a preventive medicine to the bank’s employees.

Killer Gets $600

Sixteen employees unquestioningly line up and drink the “medicine” from their own teacups. Soon the workers are sprawled over the bank’s floors, some near the bathroom where they had run for water. Twelve die from cyanide poisoning and the killer escapes with 160,000 yen--the equivalent then of about $600--while greater sums are left behind on desk tops.

THE MURDERER: Within six months, a noted 56-year-old painter, Sadamichi Hirasawa, is arrested and confesses to the crime. Although he later recants, he is convicted and in 1955 is sent to Japan’s Death Row where he has waited for more than 30 years--longer than any Death Row inmate in the world.

THE MYSTERY: How did a “very unlikely” suspect get trapped in the net of a police investigation, never to escape? What vital interest did the United States have in covering up the real culprit, as Triplett charges? Who was the killer and what was his motive?

“A complete solution to the story is probably forever lost,” Triplett conceded.

Triplett’s research has provided valuable clues to who killed the 12 bank employees and why--questions forgotten in the 1980s by all but a handful of the convicted murderer’s supporters who have filed numerous appeals to spare him the death sentence. All of them have been rejected.

High Court Hasn’t Ruled

The latest court filing requests that the testimony of Triplett and a former U.S. Army liaison officer be heard to establish the innocence of Hirasawa, now 94. The Tokyo High Court has not yet ruled.

Triplett said cultural and historical forces were at work that landed an innocent man on Death Row, including overwhelming public pressure to find a killer and a criminal justice system that required the defendant to prove his innocence rather than the state to prove his guilt.

Besides Hirasawa, who Triplett said was a “man trying to cooperate with authorities based on traditional Japanese behavior,” there was an “agency perceiving itself as infallible--the police--and a long history of brutal tactics within the police department of getting confessions. Also, the social forces were such that arrest was tantamount to conviction.”

Doctor Cleared

As is traditional in Japan when meeting strangers, Hirasawa had exchanged business cards with a doctor whose card was later used in what police regarded as a “rehearsal” for the Imperial Bank crime. The doctor was investigated and cleared.

That Hirasawa could not produce the doctor’s card and the recent appearance of a large amount of unexplained cash in his bank account--both pieces of circumstantial evidence--were used to suggest his involvement.

“From there, they made the leap to expertise with poisons, which was never really founded. They also got a confession out of him which he later repudiated and said was forced. But by that time, everything was so well in motion nothing could be stopped,” Triplett said.

Hirasawa was the last defendant in the country tried under a penal code that allowed conviction based on circumstantial evidence, Triplett said in his book. He thinks most Japanese believe the wrong man is languishing on Death Row.

Most Feel He’s Innocent

“Most of the Japanese I interviewed think Hirasawa is innocent but that doesn’t matter--what matters is that he’s convicted. Guilt or innocence is secondary to the disgrace of conviction,” he said.

In 1982, through the Freedom of Information Act, Triplett unearthed U.S. military documents from 1948 establishing for the first time that Japanese police and U.S.-occupation officers believed there was a link between the bank poisonings and a top secret Japanese Army unit, the 731 Regiment, that conducted gruesome germ warfare experiments.

The rare type of poison used, the method of administering it, and the expertise with which the killer operated pointed to the possibility that a member of the 731 Regiment was the Imperial Bank killer.

The Americans quashed an investigation into the link to protect themselves from being discovered in what he terms a “dirty deal” struck in 1947 with the 731 Regiment, Triplett said.

Army Granted Immunity

In exchange for 731 Regiment information on its biological warfare experiments in Manchuria, the U.S. Army granted immunity from war crimes prosecution to the group of scientists.

“Some 3,000 people were experimented on. They’d infect people, cure them, infect them and cure them until they were physical wrecks, and then they’d take them out and shoot them,” he said.

“Or they’d take them outside in the Manchurian winter, douse them with water so they’d freeze quickly, then bring them inside and perform thawing experiments before they’d die.”

Triplett said the Army knew of the barbaric experiments--some of which were conducted on American POWs--but decided that the deal was worth it.

The author said the 731 Regiment’s activities would have guaranteed them death sentences in the International Military Tribunal.

There also is the issue of what the Americans did with the Japanese information.

Didn’t Get to AMA

“All the evidence shows the data was taken from where it was used as weaponry and transferred to another system for use as weaponry. There’s no evidence it was ever turned over to the American Medical Assn. for positive medical use,” he said.

To keep the deal quiet, the Americans had to bury the suspected link between the Imperial Bank killings and the 731 Regiment. Triplett said they worked in subtle yet convincing ways on the police and the Japanese press to divert attention away from the 731 Regiment.

Triplett, a journalist and playwright in Washington, got caught up in the dramatic potential of the Imperial Bank story when he read an American newspaper account of it seven years ago and began researching it for use in a play or fiction.

“One of the ironies of this story is that had I written it as fiction, no one would have believed it. They’d have said the plot was an obvious contrivance to keep the pages turning,” he said.