Yoon Suk-Yeol imposed martial law last December, which he claimed would protect the country from "communist forces." He was ousted in early April when South Korea's Constitutional Court ruled in an impeachment trial that the declaration did not meet the legal requirements for a national emergency.
Cho Tae-Yong is accused, among other things, of neglecting his duties as head of Nis.
Yoon has been charged with several crimes in connection with the incident and faces a maximum sentence of life in prison or even the death penalty.
