A third round of protests against the now-suspended extradition bill in Hong Kong turned violent on Sunday night after protestors were beaten up by a group of people dressed in white shirts – suspected to be triad gangsters.

In an assault concentrated around a metro station at the Yuen Long suburb, the white-shirts assaulted pro-democracy protesters and passersby at a train station.

Footage circulating on social media show the men beating protestors with wooden sticks and metal rods.

Over 45 protestors were injured, and one critically injured, according to numbers from BBC.

The pro-democracy protestors, who had turned up in black, were especially easy to spot.

According to a South China Morning Post report, the assaulters fled before the police arrived. Questions are now being raised about why the police took so long to reach the scene.

Wide allegations of the police covering for the triad mob are rampant on social media. “#HongKong become a police state,” wrote a person on social media. “#police enforce their power by deploying triad members (white shirts).”

Posts of this kind, explaining one view of what happened on Sunday night, have now flooded social media.

Earlier in the day, close to 430,000 people had assembled to protest against the extradition bill, said the organisers, the Civil Human Rights Front. The extradition bill, though suspended, has now come to represent a broader erosion of Hong Kong’s freedoms by Beijing.

While the first few hours of the protest went planned, late in the evening several black-clad activists, some masked, defied police orders and marched to the Beijing Liaison Office. They threw eggs at and spray-painted the front of the office to voice their dissent.

In response, the riot police fired several rounds of rubber bullets and teargas at protesters, reportedly without warning.