AEGIS Weapon System Data Possibly Leaked (Japanese Navy)
THE ASAHI SHIMBUN

Data allegedly stolen by a Maritime Self-Defense Force officer contained details of an advanced defense system designed to protect a fleet from air attacks, sources said.

Kanagawa prefectural police are investigating the possibility that the sensitive information was leaked. The data was found on disks at the officer's home in January.

Investigators are also examining whether higher- ranked officers may have been involved because the MSDF sailor's security clearance was limited, sources said.

Police said the sailor under investigation is a petty officer second class aboard the Shirane, the flagship destroyer of the MSDF's Escort Flotilla One, based in Yokosuka, Kanagawa Prefecture.

Sources said the disks contained classified information, including data on a destroyer equipped with the state-of-the-art Aegis air defense system.

The system is an advanced computerized air defense system, capable of simultaneously detecting more than 200 airborne objects, such as aircraft and missiles, within a radius of 400 kilometers.

It can calculate the speed and direction of individual objects and shoot them down with guided missiles, rapid-fire cannons and high-performance anti-aircraft machine guns.

The MSDF has five Aegis-equipped destroyers, including the Kirishima, to which the officer under investigation was assigned from 1995 to 1999.

The Kirishima also belongs to the Escort Flotilla One.

Some information on the Aegis system, developed by the U.S. Navy, is protected under the secrecy protection law related to the Japan-U.S. mutual defense assistance agreement.

Under the secrecy protection law, those who leak strictly classified information can face imprisonment of up to 10 years.

In January, police arrested the officer's wife, a Chinese national, for a suspected violation of the immigration law.

When investigators searched the officer's home for evidence, the disks were found, police said.

Police are investigating how the low-ranked officer, who only had a limited ability to access information, could get the highly confidential data.

There is a possibility others authorized to access confidential information may be behind the alleged security breach, sources said.