PARK GEUN-HYE has had a tough couple of weeks: first the constitutional court upheld a parliamentary motion to impeach her on March 10th, removing her from the presidency. That step also deprived her of her immunity from investigation as president—allowing prosecutors to pounce. They had been waiting for months to serve her with an arrest warrant; on March 30th judges weighed the merits of their request in an extraordinarily long day of deliberation. Ms Park spent nine hours at a local court, as the judge deliberated. When she left her home in Seoul to attend the hearing, flag-waving supporters lined the streets; several lay down in the road in an attempt to block her path to court.

It was to no effect: shortly before dawn on March 31st, Ms Park was arrested at the prosecutors’ office. The justice who approved her pre-trial detention said that the main charges against her were “demonstrable” and that, were she allowed to leave, she might destroy evidence. Prosecutors had submitted 120,000 pages of documents to the court earlier this week concerning the 13 charges against Ms Park. In their warrant they noted that Ms Park had “let down the trust of the people”, was “consistently denying objective facts”, and “showing no signs of remorse”.

Yet her early imprisonment does not rule out a fierce battle in court: far more evidence would be required to prove criminal guilt than to justify a pre-trial arrest. The prosecutors may detain Ms Park for up to 20 days; if she is to stay behind bars, they must issue a formal indictment against her within that period. A snap presidential election has been set for May 9th. The prosecutors are expected to hurry along Ms Park’s case, and to press ahead with parallel investigations into other suspects in the scandal, while other politicians campaign for the presidency.

Ms Park’s alleged crimes include bribery, coercion, the abuse of power and the sharing of state secrets with a long-time confidante, Choi Soon-sil. If Ms Park is convicted of all 13 of her charges, she could face up to 45 years in prison. Ms Choi has already been charged with bribery and influence-peddling, and has been held at the Seoul Detention Centre for four weeks. Lee Jae-yong, vice-chairman of Samsung, sits in another cell, accused of offering a bribe of 43bn won ($38m) to Ms Park and Ms Choi in exchange for state favours (Samsung denies there was any quid pro quo).

Ms Park now joins them with her own cell at the centre. She has repeatedly apologised for disappointing the nation, but has also consistently denied any wrongdoing. Even as she maintains that she never sought personal advantage for herself, she could still be charged as a “joint principal offender”, legal experts say—if prosecutors can prove that she was involved in planning to commit extortion with Ms Choi. They already accused her of being a “co-conspirator” in November, prior to her impeachment.

Outside the prosecutor’s office, a dozen of Ms Park’s die-hard supporters waved flags covered with messages that shrieked defiance: “When martial law comes you’ll all be dead!”, and “You should be struck down by lightning”. But elsewhere the mood was one of general approval; on social media many circulated jubilant messages. Over three-quarters of South Koreans support her impeachment; millions had demonstrated for it in the streets.

Candidates in the upcoming presidential election can be expected to join them in applauding Ms Park’s arrest. But her case is unlikely to sway the outcome of the election, which looks set to be a victory for the opposition Minjoo party, which is enjoying record-high approval ratings.

Ms Park becomes the country’s third former president to be arrested over criminal allegations. Chun Doo-hwan and Roh Tae-woo, two former military-era leaders, were convicted of treason, mutiny and corruption. Both were given special pardons in 1997 after serving only two years in jail, in an attempt to promote “national harmony” by the then-president, Kim Young-sam. Yet the 13 charges against Ms Park are the most ever issued to a former head of state, and the first since South Korea’s turbulent 1990s. If she is convicted, the mood is likely to be far less forgiving.