Singapore’s Transport Minister S. Iswaran has resigned after being charged with corruption on Thursday, the prime minister’s office said, confirming a historic development for a city state that prides itself on having a squeaky-clean government.

The charges against Iswaran are part of the biggest corruption probe to engulf Singapore’s ruling People’s Action Party (PAP) in decades. The scandal, which also ensnared a hotel tycoon best known for bringing the Formula 1 Grand Prix to the city, was one in a series of controversies for the government in the past year that sent shockwaves through the country.

Iswaran is the country’s first sitting minister to be charged with a criminal offense.