In a case in which the parents were arrested for killing their 4-year-old second daughter by ingesting a harmful chemical, the mother responded to an investigation into the chemical before her arrest, saying, ``I read on the Internet that it was effective as an insecticide.'' It was learned through interviews with investigators that he gave an explanation such as "

The Metropolitan Police Department is investigating the circumstances at the time, including the purpose of purchase and usage.

In March last year, company executive Kenichi Hosoya (43) and his wife Shiho Hosoya (37) from Taito Ward, Tokyo, exposed their second daughter, Miki, who was 4 years old, to poisonous chemicals contained in car antifreeze. He was arrested on suspicion of murdering her by ingesting her with ``ethylene glycol'' and the antipsychotic drug ``olanzapine.''

In response to the investigation, suspect Kenichi has denied the charges, and suspect Shiho has remained silent.

Regarding ``ethylene glycol,'' the mother of the suspect, Shiho, responded to a voluntary inquiry before her arrest and said, ``I don't remember clearly, but if she had bought it, I think I would have bought it.'' I know it was.

In addition, an interview with investigators found that she had given explanations such as, ``I have seen on the Internet that it is effective as an insecticide.''

Although Miki had purchased ethylene glycol about a month and several days before her death, there is no evidence that she had purchased it after her death.

The Metropolitan Police Department is investigating the detailed history of the purchase, including its purpose and usage.