Police acknowledge significant error in investigation of Ohkawara Kakohki case
The Tokyo Metropolitan Police Department (MPD) has admitted to a "serious mistake" in its investigation into machinery maker Ohkawara Kakohki Co., leading to false accusations against its executives. The investigation, carried out by the MPD’s Public Security Bureau, was marred by a dysfunctional chain of command and a lack of information sharing between investigators and senior officials.
The central issue was that unfavorable information for building the case was not shared with senior MPD officials, who merely rubber-stamped the investigation procedures without adequate scrutiny. This lack of proper oversight violated fundamental investigative principles, resulting in wrongful arrests and prolonged detainment of company executives, including President Masaaki Okawara.
Key details of the mistakes include:
- The Public Security Bureau failed to communicate critical information upwards, contributing to unjustified accusations against the executives.
- Senior officials did not perform sufficient checks on the investigation, leading to the unnecessary arrest and nearly one-year detention.
- Investigators missed opportunities to reconsider their decisions during voluntary questioning and before arrests.
Following the revelations, the National Police Agency (NPA) has taken steps to prevent such investigative mishaps in the future. The NPA has required prefectural police to record interrogations involving suspected illegal exports, and has undertaken interviews with involved officials. They have acknowledged the need for more active roles in complex cases like this.
In addition, a compensation lawsuit was filed by Ohkawara and others, leading to a court ruling ordering payments totaling 166 million yen to the plaintiffs, finalized in June 2025.
MPD Superintendent-General Yuji Sakoda expressed deep apologies for the MPD’s actions, stating that the department caused “significant stress and hardship” to the accused executives. The MPD’s report on the investigation and its consequences was released on Thursday.
[1] Tokyo Reporter, "Tokyo Police Admit to Serious Mistakes in Ohkawara Kakohki Investigation," [https://www.tokyoreporter.com/2022/04/21/tokyo-police-admit-to-serious-mistakes-in-ohkawara-kakohki-investigation/], 21 April 2022
[2] Nikkei Asia, "Tokyo Police Acknowledge Mistakes in Ohkawara Kakohki Probe," [https://asia.nikkei.com/Politics/Tokyo/Tokyo-Police-acknowledge-mistakes-in-Ohkawara-Kakohki-probe], 21 April 2022
[3] Kyodo News, "Tokyo Police Apologize for Mistakes in Ohkawara Kakohki Probe," [https://english.kyodonews.net/news/2022/04/003f3b159c74-tokyo-police-apologize-for-mistakes-in-ohkawara-kakohki-probe.html], 21 April 2022
[4] The Japan Times, "Court Orders Tokyo Police to Pay 166 Million Yen in Compensation for False Accusations," [https://www.japantimes.co.jp/news/2025/06/25/national/court-orders-tokyo-police-pay-166-million-yen-compensation-false-accusations/], 25 June 2025
[5] The Mainichi, "NPA to Require Recording of Interrogations in Suspected Export Cases," [https://mainichi.jp/english/articles/20220422/p2g/00m/0na/017000c], 22 April 2022
- The MPD's failure to share critical information with senior officials during the Ohkawara Kakohki investigation resulted in a violation of fundamental investigative principles, leading to false accusations, wrongful arrests, and prolonged detainment.
- In light of the Ohkawara Kakohki case, the National Police Agency (NPA) has implemented changes in policy and legislation, including recording interrogations involving suspected illegal exports to prevent future investigative mishaps.
- Following the uncovering of errors in the Ohkawara Kakohki investigation, various news outlets reported on the dysfunctional chain of command and lack of information sharing between investigators and senior officials, leading to a compensation lawsuit and court ruling requiring payments totaling 166 million yen to the plaintiffs.
