Thomas Kwok, co-chairman of Hong Kong developer Sun Hung Kai Properties, arrives at the High Court in Hong Kong, Thursday. Pic: AP.

HONG KONG (AP) — Two billionaire brothers and the former senior Hong Kong official they’re accused of bribing have pleaded not guilty as their high profile corruption trial got underway.

Property developers Thomas Kwok and Raymond Kwok entered pleas Thursday alongside Rafael Hui in the former British colony’s biggest graft case in decades.

The Kwoks control Sun Hung Kai Properties, which built several of Hong Kong’s tallest skyscrapers and is one of the world’s biggest real estate developers by market value.

Forbes estimates the pair are worth a combined $12.6 billion, making them Hong Kong’s fifth richest.

The case has drawn widespread attention in Hong Kong, where a number of recent corruption cases involving tycoons or government figures has stoked public anger.