What began as an internal personnel dispute at the Ma Ying-jeou Foundation has evolved into an increasingly bitter and publicly fought battle that is engulfing the former Taiwanese leader whose political legacy it is meant to preserve.

Allegations of financial misconduct at Ma’s foundation have spiralled into criminal complaints, publicly traded accusations among long-time allies and an unprecedented intervention by his family.

The dispute has also raised broader questions about Ma’s health, political legacy and what effect all this will have on the main opposition party Kuomintang (KMT) ahead of the local elections later this year.

The controversy erupted in late February when two of Ma’s long-time aides – Hsiao Hsu-tsen, the foundation’s chief executive and a KMT vice-chairman, and Wang Kuang-tzu, a senior foundation employee – were dismissed over alleged financial irregularities.

Ma’s camp accused the pair of serious breaches of financial discipline, including distributing employee bonuses in cash and failing to properly record a donation from a Taiwanese businessman operating in mainland China.

The dispute escalated in May when King Pu-tsung – a former secretary general of the Taiwanese National Security Council and one of Ma’s closest associates – displayed a photograph that showed Hsiao with bundles of cash and questioned if it had been properly accounted for.