The Supreme Public Prosecutors Office and Shizuoka Prefectural Police recently released the findings of their review into the investigation and trial of former death row inmate Iwao Hakamada, who was acquitted in a retrial earlier this year. Hakamada's death sentence had been finalized decades ago for the 1966 murder of four family members of a miso manufacturer executive.

The review acknowledged the interrogation process, which subjected Hakamada to excessively long sessions often late into the night, was problematic. In some instances, he was even forced to relieve himself in the interrogation room -- an act that the Shizuoka Prefectural Police admitted was "inappropriate." The prosecutors also conceded that Hakamada was pressured to confess, with investigators making statements that assumed his guilt.

However, the Supreme Public Prosecutors Office denied allegations of evidence fabrication, which the retrial ruling in September had recognized as a key factor in Hakamada's wrongful conviction. This includes the "five items of clothing," or bloodstained garments found in a miso tank over a year after the murders, which were presented as belonging to the perpetrator. Prosecutors argued that fabricating such evidence would have been "practically impossible" given the investigation and evidence gathering policies at the time. Yet, they failed to provide convincing evidence to support this claim.

The police, for their part, interviewed investigators and employees of the miso company from that period but were unable to obtain testimonies that clarified whether evidence fabrication had occurred.

Neither the prosecutors nor the police delved deeply into the root causes of Hakamada's wrongful conviction. Despite the gravity of sentencing an innocent man to death, their reviews fell short of meaningful self-reflection. While the Supreme Public Prosecutors Office stated it "does not deny the conclusion of acquittal," it maintained there were "no problems with the arrest and prosecution" and insisted that the overall handling of the trial was largely appropriate.

This stance underscores a troubling lack of accountability. The reviews failed to identify where responsibility for the miscarriage of justice lies, leaving the public with a severely incomplete and inadequate response. Internal reviews, by their nature, have limitations, and this case highlights the urgent need for third-party oversight to ensure impartiality and transparency.

The Hakamada case is not an isolated incident. Even today, cases of forced confessions resulting from improper interrogation tactics continue to surface, indicating that the conditions that could result in wrongful convictions remain unaddressed.

The retrial system itself also warrants serious reconsideration. It took an astonishing 43 years from Hakamada's initial retrial request to his eventual acquittal. While the Supreme Public Prosecutors Office claimed the delay was unavoidable, it announced plans to strengthen the system for handling retrial requests.

However, piecemeal adjustments are not enough. A fundamental reform including mechanisms for full evidence disclosure by investigative authorities and regulations of procedures for conducting trials is necessary to address the root cause.

The Hakamada case serves as a stark reminder of the flaws in Japan's criminal justice system. The top priority must be to learn from this case and commit fully to eliminating wrongful convictions.