Tokyo prosecutors indicted on Friday a former Air Self-Defense Force officer for allegedly leaking confidential information on a U.S.-made military aircraft to unauthorized individuals.
According to the indictment, former ASDF Col. So Kanno, 58, showed two people including a trading house employee data on the capabilities of the E-2D airborne early warning plane at the ASDF's Iruma Air Base in Saitama Prefecture on Jan. 9, 2013.
The data are designated as special defense secrets based on the Japan-U.S. Mutual Defense Assistance Agreement. After showing the data to the two people on a personal computer, he also gave them a USB memory device containing the secrets, it said.
The leak came to light in Japan in October 2014 when the U.S. government notified the Defense Ministry.
The U.S. government was informed of the leak by a U.S. aircraft manufacturer, which received the data from the trading house.
Japan planned to purchase a total of 13 E-2D aircraft made by Northrop Grumman Corp. after going through the selection process in 2014, with the first one deployed to Misawa Air Base in Aomori Prefecture in March 2019.
The Defense Ministry has said the leak did not influence the selection process for the aircraft.
Kanno left the ASDF in February 2017 with severance benefits after reaching the mandatory retirement age.
"We truly regret the incident, which damaged the people's trust and could shake the relationship of trust between Japan and the United States," the ministry said in a statement.
"We will conduct our investigation based on facts to be exposed in the trial and prevent similar incidents from happening in the future," it said.