Senior police and prosecutor officials Monday directly apologized to the bereaved family of a former adviser to Japanese machinery-maker Ohkawara Kakohki once accused of an illegal export.

The officials visited the grave of Shizuo Aishima, who was found to have stomach cancer during his detention and later died while being wrongfully indicted in a case involving the machinery maker, at a cemetery in Yokohama at around 10:30 a.m.

Tetsuro Kamata, deputy superintendent-general of Tokyo's Metropolitan Police Department, Takashi Koike, head of public security at the Supreme Public Prosecutor's Office and Hiroshi Ichikawa, deputy superintending prosecutor at the Tokyo District Public Prosecutor's Office, were accompanied by Aishima's wife and two sons.

The officials knelt and prayed in front of the grave.

"We deeply apologize for conducting an illegal investigation," Kamata said.

"We sincerely apologize for the serious human rights violation caused by illegally requesting his detention and filing a prosecution, and for depriving Aishima of opportunities for medical treatment by inappropriately rejecting his bail request," Ichikawa said.

Aishima's wife replied, "I accept the apology, but I will never forgive" the illegal arrest and indictment.

It is the first time that a bereaved family has accepted an apology from investigative authorities in the Ohkawara Kakohki case. Aishima's family decided to accept the apology after the Tokyo police and the Supreme Public Prosecutor's Office released a report on Aug. 7 detailing problems related to the investigation into the company.

After the apology, the officials and Aishima's family spoke for about an hour behind closed doors. At a news conference later, his eldest son criticized the police and prosecutors for their "insufficient" review of the investigation and implementation of preventive measures.

"They are trying to settle the matter in a very vague way," the son said. "I want them to clarify their responsibility for taking my father's life."

He revealed that the family has demanded a third-party review of the investigation and the resignation of prosecutors involved in Aishima's indictment.

Aishima was arrested by the Tokyo police in March 2020 with Ohkawara Kakohki President Masaaki Okawara, 76, and others and later indicted. Aishima died at the age of 72 in February 2021, before the indictment was dropped.

The Tokyo police and Tokyo prosecutors apologized directly to Okawara and others in June, but Aishima's family had not allowed them to give an apology to the late adviser, saying that authorities had not explained the truth.

In its report on the investigation into Ohkawara Kakohki, the police said that it lacked fundamental investigative principles as an organization, and that the chain of command was dysfunctional.

The Supreme Public Prosecutor's Office concluded in the report that prosecutors had failed to thoroughly examine exculpatory evidence.