Prosecutors are preparing a report summarizing their interrogation of ex-president Park Geun-hye and with a view to indicting her.

According to prosecution sources, the prevailing sentiment is that Park must be charged since her longtime confidante Choi Soon-sil, as well as former presidential secretaries An Chong-bum and Jeong Ho-seong have all already been indicted on charges of conspiring with her.

Prosecutors are questioning other witnesses to build a rock-solid case. One source said, "We're closely examining the evidence that has been gathered so far."

Prosecutor-General Kim Soo-nam on Thursday declined to commit himself on whether he will seek an arrest warrant, which is typically only issued if a suspect is deemed a flight risk or likely to destroy evidence or interfere with witnesses.

"Whether or not to seek an arrest warrant will be decided solely based on law and principle," Kim told reporters.

There appears to be a general consensus among prosecutors that Park should be indicted before presidential candidates register for the upcoming campaign so the scandal does not blur the focus.