Ko Wen-je, once a rising star in Taiwanese politics and a presidential contender, was indicted Thursday on corruption charges.

The 65-year-old is accused of accepting half a million dollars in bribes involving a real estate dealing during his term as mayor of Taipei, as well as misreporting campaign finances during his run for president in January.

Prosecutors are seeking up to 28.5 years in prison.

Ko’s indictment deals a crucial blow to the political movement he represents, which has struck a chord with voters looking for an alternative to the ruling Democratic People’s Party and main opposition Kuomintang.