Hong Kong police have launched a multi-day raid on gangster-run establishments on Monday, July 22, to arrest those responsible for giving protesters in Yuen Long a Sunday night beating.

Officers would raid entertainment venues controlled by gangsters in Yuen Long.

The operation had begun on Monday night and is expected to last for several days.

45 people injured

White-clad thugs left at least 45 people injured after beating passers-by and protesters indiscriminately with sticks and rods.

Some 100 attackers are believed to have been responsible for Sunday night's violence.

The triads are believed to have been paid by “business interests” that may have been trying to curry favour the Chinese government.

Triad members

According to the South China Morning Post, these assailants include members of the 14K and Wo Shing Wo triad gangs.

The attacks took place after a mass anti-government march.

Attackers identified

A list of "dozens of assailants" in connection with the violent attacks at Yuen Long MTR station have been identified by the police.

"Anti-triad officers will soon launch an arrest operation in the district,” one police source told SCMP on Monday.

One of the attackers is a Wo Shing Wo faction leader, a senior triad member who acts as an enforcer.

His nickname is “Yat Poon Tsai” and is said to hold the rank of “red-pole fighter”,

The other suspect is a village head in Yuen Long, who is believed to be a 14K triad member.

His alias is “Dou Kai Hok”.

Why did mob attack protesters in Yuen Long?

SCMP reported that protesters were assaulted after an attempt to set up a Lennon Wall in Yuen Long.

Lennon Walls are walls in public spaces adorned with messages and drawings in support of anti-government demonstrations.

Yuen Long gangsters and extradition bill protesters broke out the week before the Sunday night assaults.

The gangsters had warned that they would teach protesters a lesson if they dared to come again.

Police criticised

The worst attacks took place in Yuen Long MTR station at about 10.45pm.

Two officers arrived at the scene seven minutes later, but made the assessment they did not have enough protective gear, and decided not to intervene.

They called for back-up instead.

But the attackers fled before police reinforcements of more than 30 officers arrived at the station at 11.20pm.

The police have been criticised for not being prompt enough.