Parents arrested over fatal poisoning, drugging of 4-year-old daughter in Tokyo

Parents of a 4-year-old girl were arrested Wednesday for allegedly killing her with a toxic substance and antipsychotic drug at their home in Tokyo in March last year, police said.

Kenichi Hosoya, 43, and his wife, Shiho, 37, were arrested after their daughter, Yoshiki, died from poisoning on March 13, with ethylene glycol and large amounts of olanzapine, a medicine prescribed for mental disorders, detected in her body, an investigative source said.

The police suspect that Yoshiki ingested ethylene glycol, as her parents allegedly made her consume anti-freeze additives used in engine coolants, the source said.

Ethylene glycol was also detected in the body of Hosoya's older sister, who died at age 41 in 2018, and police are investigating the circumstances surrounding her death, the source added.

Kenichi Hosoya, operator of a Japanese-style inn in downtown Asakusa, Tokyo, denies the allegations, while his wife has remained silent, the police said. Both had previously denied the accusations during voluntary questioning, according to the source.

The police have confirmed records of the couple's online purchases of the anti-freeze additive and olanzapine, the source said.

The case came to light after Hosoya made an emergency call around 9 a.m. on March 13, saying his daughter was not breathing.

When rescuers arrived, Yoshiki was found unconscious in the home's living room, and she was confirmed dead at a hospital about an hour later, the source said.

The arrested couple and Yoshiki were in a family of five with Yoshiki's older brother and sister, who were both elementary school age.

Although Yoshiki had no noticeable external wounds, the police began looking into the possibility of foul play, as Yoshiki was topless when they found her at the scene. They searched their home in August last year, and the parents voluntarily submitted to questioning, they said.

Shiho Hosoya was previously arrested for allegedly setting fire to clothing at home in 2019. The police, suspecting psychological abuse of her children, alerted a child welfare center at that time.

The center subsequently took the three children, including Yoshiki, under temporary protective care. However, the charge against the mother was later dropped.

The center said Wednesday it had been contacted five times in 2022 by Yoshiki's nursery school with reports of bruises and bumps on her face but had concluded that they were simply the result of accidents after questioning the girl and her father.