He was indicted on charges of abuse of power, dereliction of duty and perjury. But a local court twice rejected investigators' requests to arrest him.

"We plan to challenge the charges based on what is written in the (prosecutors') request for an arrest warrant," Woo's lawyer said at the first preliminary hearing at the Seoul Central District Court.

The lawyer requested three or four additional preliminary hearings to allow sufficient time to review Woo's investigation records ahead of the formal trial. But the court agreed to hold only one such hearing on June 2.

The former secretary did not appear at the trial as his attendance was not mandatory.

Both Park and Choi are currently in custody pending trial on corruption charges. (Yonhap)