"Most of the factual relations in the investigation results were not revealed during the Constitutional Court's trial," the lawyers said in an emailed statement to reporters. "Because (the charges) were not verified with evidence, they cannot be used as materials to confirm facts or form impressions during the impeachment trial."

Park Young-soo confirmed the president was an accomplice in extorting millions of dollars worth of donations from Samsung Group in exchange for business favors. He also accused her of being involved in executing a blacklist of cultural figures critical of the administration and receiving illegal medical treatments.

President Park was impeached by parliament on Dec. 9 for allegedly letting her close friend Choi Soon-sil meddle in state policymaking and colluding with her to extort money from local conglomerates.

The court is widely expected to deliver its ruling by Monday before the retirement of its acting chief, Lee Jung-mi.

Speculation was rife that the court would designate the date on Tuesday to allow three or four days' notice, which has been standard practice.

However, a court official told reporters there would be no announcement Tuesday.

Choi, meanwhile, filed a petition with a Seoul court demanding a review of the unconstitutionality of the independent counsel's probe. She has been standing trial on multiple charges related to the scandal.

"The law on the independent counsel was recommended solely by the Democratic Party and the People's Party, giving special favors to certain factions," her lawyer Lee Kyung-jae said. "The unconstitutionality is very grave and clear."

Park Young-soo was appointed by the president upon the recommendation of the opposition parties. (Yonhap)