Masumi Hayashi (poisoner)

Masumi Hayashi
Born	(1961-07-22)July 22, 1961
Criminal penalty	Death sentence

Killings
Date	July 25, 1998
Span of killings	1998–
Location(s)	Wakayama Prefecture, Japan
Killed	4
Injured	64
Weapons	Arsenic
Date apprehended	October 4, 1998

Masumi Hayashi (林眞須美, Hayashi Masumi, born July 22, 1961) is a Japanese woman convicted of putting poison in a pot of curry being served at a 1998 summer festival in the Sonobe district of Wakayama, Wakayama, Japan.

Summary

A communal pot of curry being served to residents of Sonobe district, Wakayama, was poisoned with at least 1,000 grams of arsenic — enough to kill over 100 people — on July 25, 1998.

Two children and two adults fell sick and died after consuming the curry, and 63 others suffered from acute arsenic poisoning. Killed in the incident were 64-year old Takatoshi Taninaka and 53-year old Takaaki Tanaka (council president and vice president of Wakayama, respectively), 10 year-old Hirotaka Hayashi, and 16-year-old Miyuki Torii.^[1]

Attention quickly focused on 37-year-old Hayashi, as she was seen by a witness at the curry dish, and she had easy access to arsenic because her husband was an exterminator. After her arrest, she and her husband were indicted on a number of insurance fraud charges as well. Her husband was subsequently convicted and imprisoned for insurance fraud. Prior to the murders, Masumi had been an insurance saleswoman. Masumi was also tried for three other attempted murders by poison that had occurred during the previous 10 years, with the motive in those cases being life insurance benefits. She is believed to have tried to kill her husband at least once. The motive of the mother of four in this case is said to be anger at her neighbours for shunning her family. The arsenic found in the curry was identical to arsenic she had in her own home from her husband's extermination business.

Trial

At her trial she pleaded innocent, but she was sentenced to death in 2002. On June 28, 2005, a high court in Osaka upheld her death sentence. However, her lawyers insisted on her innocence because only circumstantial evidence existed.^[2]

On April 21, 2009, the Supreme Court of Japan rejected her final appeal.^[3]^[4]

In July 2009, Hayashi formally petitioned for a retrial. The court's decision is pending.^[5]

Symptoms of survivors

4 died and 63 survived. Acute symptoms during the first 2 weeks included nausea, vomiting, abdominal pain, diarrhea, weakness, headache, exanthem, enanthem, hypopotassaemia, hyperphorpahataemia, leukocytosis, leukopenia, thrombocytopenia, anemia, increase in aspartate transaminase, increase in alanine transaminase, hypotension, prolonged QT interval, T wave alternans, ST segment change, cardiomegaly, pulmonary edema, pleural effusion. (including symptoms of more than 20%)

Dermatological findings during the first 2 weeks; subconjunctival hemorrhage (24%), flushing erythema (8%), facial oedema (21%), maculopapular eruption (13%), acral desquamation (17%).

Dermatological findings in 21 patients at 3 months; Beau's lines (52%), Mees' lines (48%), total leukonychia (33%), onychodystrophy (24%), periungual pigmentation (43%), acral desquamation (19%).^[6]

Fallout

Hayashi's case gained a lot of public attention. The crime inspired a wave of copycat poisonings.^[7]

References