The woman at the centre of a scandal roiling South Korea met Monday with prosecutors examining whether she used her close ties to President Park Geun-hye to pull government strings from the shadows and amass an illicit fortune.

"Please, forgive me. I'm sorry," Choi Soon-sil, a cult leader's daughter with a decades-long connection to Park, said inside the Seoul prosecutor's building, according to Yonhap news agency, as she wept. "I committed a sin that deserves death."

Choi, wearing a bucket hat and scarf, her hand pressed to her mouth, was nearly knocked off her feet several times as she tried to walk through a massive crowd of media, protesters and security surrounding the building's entrance. YTN TV station reported that Choi lost her shoe as the throng converged on her.

Choi Soon-sil, centre left, a cult leader's daughter with a decades-long connection to President Park Geun-hye, is surrounded by prosecutor's officers and media upon her arrival at the Seoul Central District Prosecutors' Office in Seoul on Monday. (Lee Jin-man/The Associated Press) Protesters screamed: "Arrest Choi Soon-sil" and "Park Geun-hye should resign."

The scandal exploded last week when, after weeks of speculation, Park acknowledged that Choi had edited some of her speeches and provided public relations help. Widespread media reports say that Choi, who has no official ties to the administration, may have had a major role in government affairs.

Convoluted interfamilial history

Investigators are trying to determine the scope of access Choi had and whether she was given sensitive presidential documents. They have raided the homes of some officials in the presidential Blue House as part of the investigation.

Park has fired some of her top aides to try to contain the fallout as thousands of people have protested in the streets and some lawmakers and the public have called for her resignation or impeachment.

It's not clear how much influence Choi had. But many South Koreans believe there is much more to the story than Park has acknowledged, and the frenzy surrounding the scandal threatens her presidency.

Choi, 60, returned home Sunday from seclusion in Germany. It is unclear if there will be any details revealed from her meeting with prosecutors.

Choi has previously said she helped Park but didn't know if she was seeing confidential information. Choi's attorney, Lee Kyung-jae, told reporters earlier that Choi "apologizes deeply for causing the people humiliation and despair."

Choi has been close to Park since Choi's father, the leader of a religious cult, attached himself to Park by reportedly convincing her that he could communicate with her assassinated mother. The man who later murdered Park's dictator father, President Park Chung-hee, is said to have claimed that he staged his attack in part because Park Chung-hee wouldn't keep Choi's father away from the young Park Geun-hye.

Accused of profiting from business donations

Media reports said the younger Choi used her connection to Park to pressure businesses to give money to two non-profit organizations she controlled, the Mir and K-Sports foundations; she then allegedly used some of the organizations' official funds for personal purposes. South Korean media speculated that the two foundations collected about 80 billion won ($70 million US) in donations from South Korea's largest business groups in just a few months.

Anti-government protesters demonstrate as a confidante of South Korean President Park Geun-hye appears at the Seoul Central Prosecutors' Office suspected of interfering in state affairs. (Woohae Cho/Getty Images)

The president of Ewha Womans University has also resigned amid protests over allegations that Choi used her connections to Park to get her daughter into the elite school and then secure special academic treatment.

Political and business corruption remains widespread in South Korea, which has only had full democracy since the late 1980s, when it shook off decades of military dictatorship. But this scandal has struck a chord in a way that previous ones have not.

Part of it has to do with Park Geun-hye and her past, which is deeply entwined with South Korea's recent, tumultuous history. The legacy of her father is still divisive. Supporters see him as saving South Korea from poverty and irrelevance by building up the economy from the rubble of the Korean War. Opponents say that the economic development came at the expense of massive human rights abuses, including the torture and death of dissidents.

Elected in 2012, Park has been accused by critics of governing in an imperial manner, relying only on a few longtime confidantes and limiting her interaction with the press, the public and even parts of the government.

Even so, Park's close confidantes were assumed by most South Koreans to be in the government. That she may have been outsourcing decisions to someone outside of government, and someone connected with a murky, lurid backstory, has incensed many. Nearly 10,000 people took to the streets in protest over the weekend.

To try to contain public anger, Park has reshuffled her aides, appointing a new senior secretary for civil affairs and new chief secretary for public affairs. She also accepted resignations from several officials in her inner circle; one of those, an aide of Park for nearly two decades, allegedly has links to the scandal.