Prosecutors looking into the December 3 martial law incident continue to question key military officials as they prepare to hand over the case to the Corruption Investigation Office for High-Ranking Officials.

According to sources close to the investigation, Capital Defense Commander Lee Jin-woo is being questioned Thursday as a suspect regarding the deployment of troops to the National Assembly under martial law.

Lee was detained Monday after being apprehended on Friday with a warrant. 

Earlier, prosecutors grilled Col. Kim Hyun-tae, the commander of the 707th Special Mission Group under the Army Special Warfare Command, for some 17 hours on Wednesday. 

The group was deployed to the National Assembly after President Yoon Suk Yeol declared martial law on December 3. 

After the investigations, Kim met with reporters and denied allegations that members of his group were virtually imprisoned for around two weeks after the martial law incident. 

He also dismissed suspicions that his group had carried out martial law readiness training from the beginning of the year.