The pattern investigators established
Kakehi formed relationships with older men, including through matchmaking services. Prosecutors said she administered cyanide after gaining their trust and stood to benefit financially from inheritances, insurance or debts. The criminal case ultimately focused on three completed murders and one attempted murder.
Those convictions concerned her husband Isao Kakehi and two other men, Masanori Honda and Minoru Hioki, as well as the attempted killing of Toshiaki Suehiro. Reporting has connected Kakehi to additional deaths, but those other cases were not part of the final murder convictions. This page therefore does not present a larger victim total as established fact.
Investigation and prosecution
Kakehi was arrested in 2014 after toxicology findings in the death of her husband drew investigators' attention to cyanide. The inquiry then expanded to earlier partners and acquaintances. Prosecutors assembled a circumstantial case using toxicology, financial evidence and the repeated pattern of relationships and sudden deaths.
In 2017, the Kyoto District Court convicted Kakehi of three murders and one attempted murder and imposed the death penalty. Her lawyers challenged the verdict, including arguments about her mental condition and dementia, but the convictions survived appellate review.
Supreme Court decision
On June 29, 2021, Japan's Supreme Court rejected Kakehi's appeal and upheld the death sentence. Contemporary reporting quoted the court as finding that she repeatedly used cyanide after inducing the men to trust her as a partner, and that the killings showed calculated intent.
Retrial request and death in custody
Kakehi later sought a retrial concerning one of the murders. The Kyoto District Court rejected that application in March 2024, according to reporting cited by The Japan Times.
On December 26, 2024, Japanese media reported that the 78-year-old death-row prisoner died after being found unresponsive at the Osaka Detention Center and taken to a hospital. Because she died before any execution, her current status is recorded as deceased in custody rather than executed.
Timeline
2007: prosecutors later establish an attempted cyanide murder of Toshiaki Suehiro.
2012–2013: three men are murdered in the series for which Kakehi is ultimately convicted.
2014: Kakehi is arrested as the cyanide investigation expands.
2017: Kyoto District Court convicts her of three murders and one attempted murder and sentences her to death.
June 29, 2021: Japan's Supreme Court upholds the death sentence.
March 2024: a retrial request concerning one of the murders is rejected.
December 26, 2024: Kakehi dies in custody after being taken from Osaka Detention Center to a hospital.
Current status
The case is classified as solved / adjudicated. Kakehi's convictions for three murders and one attempted murder remained intact when she died in custody in 2024. The site does not count uncharged or unproven deaths as additional confirmed victims.