The scandal that led to the jailing of former South Korean president Park Geun Hye for 24 years on Friday (April 6) came to light in September 2016, when thousands of students at Seoul's prestigious Ehwa University staged a protest against the manipulation of the academic records of a student.
That student was Chung Yoo Ra, the only child of Choi Soon Sil, by most appearances a rich housewife.
But investigations by journalists gradually uncovered how the 61-year-old had abused her close friendship with Park - which goes back to the 1970s when Park was the acting First Lady to her dictator father Park Chung Hee - to cream billions of won off Korea's powerful family conglomerates or "chaebols", including Samsung and Lotte.
Choi's father Choi Tae Min was described by a US diplomat as a Korean Rasputin who had "complete control over Park's body and soul". After he died in 1994, Choi became Park's closest confidante and came to wield so much influence that she dictated Park's wardrobe, edited her presidential speeches, and decided who could work for the president.
She exploited her position not just for financial gain, but also to build the equestrian career of her daughter, who was admitted to Ewha and selected to represent South Korea in the 2014 Asian Games.
Besides Choi, Park surrounded herself with cronies that brooked no dissent, to the extent of drawing up a blacklist of 10,000 artists and entertainers seen as critical of her government.
Her downfall was sealed by a fallout between Choi and her rumoured lover Ko Young Tae. Ko tipped off two broadcasters to the abuse of power by Choi and Park, including by secretly videotaping Choi bossing over two presidential aides and giving the footage to the media.
A Seoul TV station had also obtained Choi's tablet computer containing many confidential presidential documents, including drafts of Park's speeches.
Weeks of massive anti-Park protests broke out after the media exposes, leading to Park's impeachment by parliament in December 2016.
She was indicted for corruption and other charges in April last year. Similar charges were laid against Choi, while Samsung Samsung Group chief Lee Jae Yong and Lotte Group chairman Shin Dong Bin were charged with bribing Choi.
Choi was convicted and sentenced on Feb 13 to 20 years in jail. Lee was given five years last August but set free on Feb 5 after his sentence was suspended on appeal. Shin is appealing his 30-month jail sentence.