Kuo Wen-ji, who was a rising star in Taiwanese politics and a presidential candidate, was indicted on corruption charges on Thursday.
The 65-year-old is accused of accepting half a million dollars in bribes related to a real estate transaction during his tenure as Taipei mayor, as well as misreporting campaign funds during his presidential run in January.
Prosecutors are seeking up to 28.5 years in prison.
The indictment against Ko deals a decisive blow to the political movement he represents, which has struck a chord with voters looking for an alternative to the ruling People's Democratic Party and the main opposition Kuomintang.
Ko, who denied the corruption allegations, was arrested in September and detained.
He was among 11 people prosecuted, prosecutors said Thursday. Several other members of his Taiwan People's Party have also been accused of embezzling political donations.
The dark horse in the presidential elections in JanuaryKo won more than 25% of the votes, which is not much less than the ruling party's candidate Lai Ching-te, who got 40%.
Observers said at the time that although Ko came in last place among the three presidential candidates, his significant performance indicated voters' demand for a more pluralistic political landscape beyond the two major parties.
Coe rose to prominence by describing himself as a third choice outside the two major parties. He criticized the DPP for stirring up tensions with Beijing, which considers the autonomous island its own territory, but also blamed the Kuomintang for being too deferential.
After supporting protesters during the anti-Beijing Sunflower Movement in 2014, Ko was elected mayor of Taipei as an independent candidate.
He won a second term in 2018, but his policies appear to have changed and he has expanded Taipei's relationship with mainland China.
It has long been known as a wildcard in Taiwanese politicsKo sparked controversy due to his bold rhetoric and strange ideas in his election campaign. He has been described as a “gaffe machine” and starred in a rap video in his 2018 re-election bid.
After his defeat in the presidential election, he vowed not to give up on his political career, and was expected to seek the presidency again in 2028. But it remains to be seen whether his party will be able to recover from the wave of prosecutions.
Ko's arrest sparked protests from his allies and supporters, who accused the Democratic Progressive Party of using the charges to suppress its opponents.