A lawyer for the jailed woman at the center of the biggest South Korean political scandal in decades said Thursday that prosecutors threatened to "annihilate'' her family and used other abusive language during questioning.

The woman, Choi Soon-sil, a longtime friend of President Park Geun-hye, has been arrested for allegedly interfering in state affairs and extorting money from businesses. Park was impeached last month over the scandal and the Constitutional Court is reviewing whether to formally end her rule.

Choi created a stir Wednesday by shouting out accusations about prosecutors when she was brought to the office of prosecutors. Choi screamed out to reporters that the investigation was unfair and said she had been forced to confess untrue things about her relationship with Park. 

There is huge pressure on prosecutors amid widespread fury in South Korea over the charges against Choi and Park. Millions of South Koreans have taken to the streets to protest what prosecutors have described as collusion with Park that allowed Choi to pull government strings from the shadows. 

But on Thursday, her lawyer accused prosecutors of questioning Choi without informing him late on Christmas Eve in what he called a violation of a law that guarantees the right to counsel. 

During questioning that he said lasted until 1 a.m. on Christmas Day, the lawyer, Lee Gyeong-jae, said prosecutors used "very shocking'' language that abused Choi's human rights. He said they threatened to "annihilate'' Choi's family and make "Choi and even her grandson live (in shame) so that they cannot hold their faces up.'' 

Lee said the threats to destroy a person's family was similar to the feudal language used during the Chosun Dynasty, which ruled the Korean Peninsula for 518 years before it was colonized by Japan in 1910.

Lee accused prosecutors of trying to induce Choi to confess to things she had not done.

Lee and Choi have previously raised similar accusations, but prosecutors dismissed them as groundless.

Prosecutors said Wednesday they plan to question Park and search her office by early next month. Park has said she's willing to undergo questioning by the special prosecutors investigating the wide-ranging scandal. It's not clear if her office will allow the search of the presidential Blue House.

To remove Park from office permanently, at least six of the Constitutional Court's nine justices must support her impeachment. Two of the nine justices will leave office in coming weeks -- one on Jan. 31 and the other on March 13 -- when their terms of office end. But six "yes'' votes are still required even if some seats are vacant.

Court head Park Han-chul, one of the departing justices, said the court's ruling should be issued by March 13. (AP)