Tokyo couple faces new murder charges in connection with two deaths

A couple suspected of fatally poisoning their four-year-old daughter and the husband's sister were served new arrest warrants Friday for allegedly killing the husband's father six years ago, Tokyo police said.

The third arrest warrant against Kenichi Hosoya, 43, and his wife Shiho, 38, says they are suspected of murdering his 73-year-old father Isamu Hosoya by poisoning him with ethylene glycol at his home between August 2017 and June 2018 . a toxic substance contained in antifreeze. He died of sepsis in hospital on June 5, 2018.

According to police, the two remained silent about the latest accusation.

Kenichi Hosoya inherited an apartment and a piece of land after his father's death. Investigators suspect that the father and the couple argued over inheritance and the management of the family business.

They determined Isamu Hosoya likely consumed ethylene glycol after analyzing his blood tests and medical records.

Examinations of the couple's smartphones and laptops revealed records of antifreeze purchases in August 2017, while messages between the couple on the messaging app Line suggested their involvement in the alleged murder, including texts that Isamu Hosoya “should die.”

Investigators are also investigating the death of Kenichi Hosoya's mother in January 2018. His parents and sister all died in the first half of 2018.

Ethylene glycol is a colorless, odorless liquid with a slightly sweet taste that dissolves easily in water. Consuming large quantities can cause damage to the central nervous system and kidneys and ultimately lead to death.

The two were first arrested in February for the alleged murder of their daughter Yoshiki in March 2023. In March this year, they were served with new arrest warrants for the alleged murder of Kenichi Hosoya's older 41-year-old sister Minako Hosoya in April 2018.

The two were charged in September with the alleged murder of Minako Hosoya after six months of psychiatric evaluations to determine whether they could be held criminally responsible.

The investigation into her daughter's death is ongoing.