Prosecutors are now investigating Ko and his former deputy mayor, Peng Zhen-sheng, for failing to account for money they made during their time in office.
Both have said the money came from legitimate sources, such as public speaking engagements, but prosecutors say the money could not be explained by their incomes as public servants.
Last week, Ko was charged with accepting at least NT$17 million (US$520,300) in bribes over a real estate transaction while serving as Taipei’s mayor from 2014 to 2022 and misappropriating a further NT$42 million in political donations – accusations he denies.
Before the latest probe was announced, prosecutors were pursuing a prison sentence of up to 28.5 years.
Ko has said the charges against him are “politically motivated” but resigned as head of the TPP this week.
