NHK has obtained documents on the executions of the leader and 12 former senior members of the Aum Shinrikyo cult.
The Justice Ministry released the documents through the information disclosure system. But most of the details have been redacted, including the discussions about the death sentences that were carried out in July.
Ministry officials cite concerns about the violation of individual rights and the possible impact on other executions.
Shizue Takahashi, a representative of the victims of the 1995 sarin gas attack on the Tokyo subway system, says there is not enough information in the documents to determine whether legal procedures were followed correctly.