The Corruption Investigation Office for High-ranking Officials(CIO) investigating alleged power abuse by former defense minister Song Young-moo launched a raid of the Defense Counterintelligence Command.

The investigative unit announced that the raid had begun on Tuesday, four days after a search seizure at the defense ministry headquarters as well as the residences and offices of the ex-minister, one of his former aides and a former ministry spokesperson.

Song is accused of forcing senior ministry officials in July 2018 to draw up and endorse documents that refuted a media report that said that he denied any legal problems with a controversial contingency martial law plan under the Park Geun-hye government.

The martial law plan was prepared by the Defense Counterintelligence Command's predecessor, the Defense Security Command, when the former president faced impeachment in 2017.

Based on the gathered evidence, investigators are expected to summon Song and others for questioning.