A group of masked thugs in white shirts attacked protesters in a Yuen Long, Hong Kong train station Sunday night, triggering speculation that organized criminal gangs, called “Triads,” are now involved in the efforts to quell the pro-democracy protesters.

Nearly 50 people were injured when the gang attacked innocent bystanders and protesters who were dressed in black. In the attack, using bamboo sticks and other objects, at least one person was critically injured. The protesters had just left a confrontation in central Hong Kong where they faced tear gas fired at them by police who accused the protesters of throwing bricks and other items.

Hong Kong has been in turmoil for about four weeks, stemming from the government’s attempt to pass an extradition bill that would allow Chinese authorities to take suspected law breakers back to Mainland China. Fear of trumped-up charges and human rights violations have stoked the protests.

The Hong Kong Police Force has been accused of having a weak response to calls from victims of the train station attack and there is suspicion that the Hong Kong government, backed by Chinese supporters, are involved.

Stephen Lo, the Hong Kong Police Force chief explained that the police force was occupied with anti-government protests in other parts of the city and dismissed the charge that the police were involved in the mob violence as a “smear.”

The Triads have been in existence in China since the 17th century, and are known for doing the “dirty work” of the Chinese government when the police force cannot accomplish the task at hand. In 2014, they intimidated protesters during the Umbrella Movement in Hong Kong. BBC reported that the Triads had been paid to attack the demonstrators. This could explain the lack of police presence at the train station.

The response of China to the events in Hong Kong is interesting and has not gone un-noticed by the global press. The Wall Street Journal reported that coverage by the state-run media on the protests was an attempt to “stoke public anger” against the protesters. The recent defacement of a liaison office in Hong Kong was called an open challenge to “the authority of the central government.

Vox news reported that President Donald Trump, himself a controversial figure, was recently asked by Chinese President Xi Jinping to curb his criticism of China about the Hong Kong protests as a condition for resuming trade talks. Trump may be “straddling the fence” a bit when he said that Beijing has behaved “very responsibly” and “I hope that President Xi will do the right thing.” Then he noted that “it has been going on a long time.”