Public prosecutors indicted a former Air Self-Defense Force officer Friday for allegedly leaking classified early-warning aircraft performance data provided to Japan by the US government.

The Tokyo District Public Prosecutors Office suspects that So Kanno, 58, the former ASDF colonel, violated the law to protect secrets under the Japan-US mutual defense assistance agreement.

The prosecutors' office did not disclose whether he has admitted to the charges.

According to the indictment and other sources, Kanno showed special defense secrets, including on the performance of the E-2D early warning aircraft, on a computer screen to employees of a Japanese defense equipment trading house at the ASDF's Iruma base in Saitama Prefecture, near Tokyo, in January 2013.

Kanno, who was a section chief at the ASDF's Air Development and Test Command at the time, is also suspected of giving a flash memory stick containing the data in question to the employees.

He obtained the data in September 2010 when he was head of the defense division's research office at the Headquarters of the Air Defense Command.

The data leak came to light after the trading house employees gave the classified information to a US company that is a rival of the E-2D developer, investigative sources said. The two employees were apparently unaware that the data were classified defense secrets.

Kanno was arrested last month by Tokyo's Metropolitan Police Department.

JIJI Press