Overview

• The intrusion occurred on Oct. 6 between about 4:45 a.m. and 5:30 p.m. JST, when at least one police email account was taken over.
• Approximately 120,000 emails were generated from the system and about 19,000 were delivered to recipients in Japan and abroad.
• The incident was uncovered after staff reported difficulty sending messages, prompting checks that revealed the mass outbound traffic.
• Investigators have not verified the contents of the emails, and officials say the setup should not expose internal police data.
• Authorities are investigating the cause, tightening mail server controls, and handling the case as unauthorized access originating from overseas.