The Ground Self-Defense Force is suspected of systematically covering up a criminal case involving a colonel in 1994, the Defense Agency said Thursday.

The case involves Col. Yasunobu Hideshima, 53, who was arrested Monday on suspicion of allowing three civilian friends to fire live rounds during a November 1994 drill in Shizuoka Prefecture. Hideshima's rank is the fifth-highest of the 18 GSDF ranks.

Military police arrested Hideshima and the three civilians only after the media reported the case in January.