SEOUL -- South Korea's special counsel investigating former president Yoon Suk-yeol's short-lived martial law imposition on Saturday indicted the ousted leader under detention on additional charges.

Cho Eun-suk, independent counsel leading the investigation into Yoon's insurrection and other charges, prosecuted Yoon for abusing power, obstructing justice, writing bogus official documents, violating the presidential records act and committing other wrongdoings.

Yoon was charged with failing to follow proper procedures for the martial law imposition, ordering the presidential security service to block attempts in January to arrest him and giving order to delete information on security phones offered to military commanders.

A warrant to detain Yoon, sought by the special counsel team that launched its investigation on June 18, was issued nine days earlier for fear of his destroying evidence.

Yoon was apprehended in presidential office on Jan 15 and was indicted under detention on Jan 26 as a suspected ringleader of insurrection, but he was released on March 8 as prosecutors decided not to appeal against the court's release approval.

The constitutional court upheld a motion to impeach Yoon on April 4 over his botched martial law bid last December, officially removing him from office.