South Korean anti-corruption agency asked prosecutors to indict impeached President Yoon Suk Yeol on insurrection charges after wrapping up a preliminary investigation into his ill-fated martial law declaration.

South Korea’s impeached president has denied that he ordered the military to drag lawmakers out of the National Assembly to prevent them from voting to reject his martial law decree last month, as he appeared for the first time before the Constitutional Court that will determine his fate.

The so-called Choongampa faction, a group with origins in the private school in Seoul where imprisoned South Korean President Yoon Suk-yeol studied in the 1970s, appears to be a key element in the plot behind his recently foiled decision to declare martial law.