Choi Soon-sil, the woman accused of currying favour with South Korean president Park Geun-hye to gain influence and money, has been ordered to appear before a parliamentary hearing.
The embattled Ms Park, who denies colluding in corruption, faces an impeachment hearing on Friday but she is sitting tight and insists she will not step down until a smooth transition can be assured.
Millions have demonstrated for the past six weekends calling for her resignation in the biggest political scandal to rock South Korea since democracy was restored in the late 1980s.
The second round of the parliamentary hearing started in Seoul on Wednesday. It is questioning the heads of some of South Korea's biggest "chaebols", or industrial conglomerates, including Samsung, Lotte and Hyundai about large donations to charities run by Ms Choi.
Ms Choi is suspected of subsequently siphoning off 77.4 billion won (€62 million) from the foundations for various projects, including paying for her daughter’s equestrian training.
Ms Choi is the daughter of Ms Park’s mentor Choi Tae-min, a “Rasputin-like” leader of a shamanistic cult who died in 1994. The family has been close to the Korean leader since the assassination of Ms Park’s mother and then-first lady, Yook Young-soo in 1974. Her father, president Park Chung-hee, was killed in 1979.
So far, the hearing has summoned 27 people, but 14 have yet to show up at the National Assembly, including Ms Choi Soon-sil and her family members.
Ms Choi is in police custody but has refused to attend the hearing, saying her health will not permit it.
This week Ms Park said she would accept the outcome if she is impeached.
“If the impeachment motion is passed, I am ready to remain calm and composed for the country and the people,” she said.
Other issues
Aside from the corruption argument, the issue that appears to have riled many Koreans most of all is Ms Park’s handling of the Sewol ferry sinking in April 2014, which left more than 300 passengers, mostly young students, dead or missing.
Ms Park is accused of having her hair done and of receiving beauty treatments on the day of the accident, when she reportedly went missing for seven hours.
The investigation has also questioned former vice-sports minister Kim Chong about allegations that he tried to blackmail Olympic gold medallist and world champion swimmer Park Tae-hwan not to take part in the Rio de Janeiro Summer Olympics, after he failed a doping test but won an appeal to compete after serving his suspension.
Mr Kim told the hearing “the suspicion is attributable to a misunderstanding”, Yonhap news agency reported.
In another bizarre element to the tale, there has been intense focus on the use of taxpayers’ money to buy medicines, including skincare products and the erectile dysfunction treatment Viagra, which the Blue House (the executive office and official residence of the South Korean head of state) said had been used to counter altitude sickness.
This week, the chief presidential doctor, Lee Sun-woo denied that Ms Park had received a series of skincare and anti-ageing injections, including placenta injections, for cosmetic purposes, but said he had prescribed them using his “medical judgment” to treat various health conditions.
