Choi Soon-sil, the 60-year-old woman at the center of the affair, returned from Europe to South Korea and voluntarily handed herself into police, who have two days to decide whether to formally apply for an arrest warrant.
Authorities are investigating whether Choi, a long-time friend of Park, used her personal relationship with the president to gain access to classified government documents, influence government decisions, and solicit contributions from businesses to non-profit foundations under her control. These contributions reportedly amounted to US$ 69 million.
"Choi has denied all of the charges against her, and we're concerned that she may destroy evidence," state-owned news agency Yonhap quoted an unnamed prosecution official as saying. "She has fled overseas in the past, and she doesn't have a permanent address in Korea, making her a flight risk."
The current scandal came to light in September, after a local television report alleging wide-ranging influence by Choi over Park’s administration. Park initially shrugged off the accusations, but growing public anger has since led her to fire her chief of staff and seven presidential aides, and to issue a public apology.
Adding to fascination with the scandal is the strange background to the two womens’ relationship. Choi is the daughter of late sect leader Choi Tae-min, who grew close in the 1970s to a young Park after her mother was killed in an assassination attempt against her father, military strongman Park Chung-hee.
Opponents of Park have long criticized her ties to the elder Choi, giving him the moniker of "Korean Rasputin" – a reference to the Russian mystic who insinuated himself into the court of Russia’s last Tsar.
"Rumors are rife that the late pastor had complete control over Park's body and soul during her formative years and that his children accumulated enormous wealth as a result," a U.S. Embassy official in Seoul wrote in a leaked 2007 State Department cable.
Park’s dismissal of staff members and public apology have done little to quell public anger. Early Tuesday, a man drove a construction vehicle into the Seoul District Prosecutor’s Office, damaging the facility and injuring one security guard.