The military prosecution arrested a retired colonel last Wednesday on charges of leaking the secret blueprints of the Joint Chiefs of Staff building to a construction firm without security clearance, the Defense Ministry said Thursday.

The retired official, surnamed Kim, is alleged to have allowed the firm to construct anti-electronic magnetic pulse facilities in the JCS building in Seoul and offered the building’s layout for the job.

The prosecution has also been investigating a sergeant major, surnamed Park, on charges of offering the JCS blueprints to the firm under Kim’s directive. Investigators have decided to further investigate Park without detaining him.

Several months ago, the prosecution secured “circumstantial evidence” about the leak of the classified JCS designs. It raided some 20 places, including the main offices of the private firm in question, in mid-May, officials said.

As for the firm facing charges of illicitly collecting military secrets, the prosecution has been investigating its president primarily over how he obtained the drawings.

Investigators said they had retrieved all the leaked blueprints. They vowed to improve internal security rules and regulations concerning the management of military blueprints to prevent a repeat of the incident. The Defense Ministry also plans to put in place an officer in charge of the security of confidential designs for military facilities.

By Song Sang-ho (sshluck@heraldcorp.com)