The Supreme Court on April 21 upheld lower court rulings that sentenced a woman to death over a 1998 fatal curry poisoning case in Wakayama Prefecture, dismissing her not guilty plea and bringing to an end a trial process that has lasted nearly 10 years.

Masumi Hayashi KYODO PHOTO

The lower courts convicted Masumi Hayashi, 47, of killing four people and poisoning 63 others by lacing a curry stew with arsenic during a community summer festival in the city of Wakayama. Although there was no direct evidence to prove her involvement, the courts determined circumstantial evidence left no room for doubt.

Hayashi's lawyers said earlier they plan to file a petition for a retrial.

Hayashi's motive remained unclear in the district and high court rulings, but prosecutors insisted that she was "infuriated by feeling alienated from housewives in the neighborhood" when she went to the place where the curry was being cooked on the day of the incident.

At the top court, Hayashi's defense counsel denied the credibility of expert scientific analysis that showed the arsenic in the stew was identical to samples found in Hayashi's home and other places related to her, and of testimony by a neighbor that there was a period when Hayashi was watching the stew pots alone.

Meanwhile, victims of the incident are still suffering from the aftereffects of arsenic, with one woman saying, "I feel pain because of my deformed fingernails and toenails."

The incident took place July 25, 1998. A 10-year-old child and a 16-year-old high school girl were among those who died after eating the poisoned curry.