Japan‘s Supreme Court, on Tuesday, upheld a death sentence of Chisako Kakehi for the murder of three men and the attempted murder of a fourth. The victims included her husband, as well.

The 74-year-old serial killer, often referred to as the ‘Black Widow‘, allegedly received large insurance payouts after poisoning her victims with cyanide, CNN reported, quoting public broadcaster NHK.

Chisako was sentenced to death in 2017 for the murders that she conducted between 2007 and 2013 in Kyoto, Osaka and Hyogo.

Her legal team had appealed the death sentence, saying that she was suffering from dementia and is not capable of partaking in a criminal trial.

According to her lawyer, CNN reported, that Supreme Court rejected her appeal.

“She used the matchmaking agency to get acquainted with elderly victims one after another and poisoned them after making them trust her,” said Judge Yuriko Miyazaki in the ruling, according to NHK, CNN quoted.

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“It is a ruthless crime based on a planned and strong murderous intention.”Miyazaki added that “even with due consideration given to the defendant’s favorable circumstances, such as being old, the death penalty is unavoidable.”

However, her death sentence date has not been released.

The investigations began after Chisako’s husband died in 2013, less than two months after their wedding. An autopsy report revealed that he had cyanide in his stomach and blood. The ‘Black Widow’ was arrested 11 months later.

Cyanide was also found in one of her fiance who died in a motorcycle crash.

According to a judge in 2017, she was with the victims when they were poisoned and began the process of inheriting the assets immediately after their deaths.

As per a CNN report, she is not the only black widow killer in Japan. Kanae Kijima, another notorious serial killer, is awaiting a death sentence after being found guilty of killing three men.