A 22-year-old passerby has been arrested and faces a possible charge of “disorder in public” after taunting a group of riot police with questions about their ability to tell right from wrong.

On Monday night, the 22-year-old man surnamed Chu stood on the sidewalk at the intersection of Nathan Road and Boundary Street in Kowloon while a group of riot police stood on an opposite street.

The riot police were deployed as protesters had surrounded the Mong Kok Police Station.

It was understood that Chu, wearing a white T-shirt at that time, shouted at the officers: “Sir, did you drop something? Did you lose your conscience, [your] humanity?” and “Where were you on July 21? Where were you when gangsters beat up people?”

A reporter from Apple Daily captured the moment, which saw at least five riot police chase Chu, hit him with batons several times and subdue him in the middle of the road.

Chu used his hands to protect his head while a police officer kicked him a few times. Chu cried: “I have done nothing wrong, I was only scolding you.”

Chu suffered head injuries, as blood was seen coming from his head on to his T-shirt. He was taken to a police vehicle and later sent to hospital for medical treatment. He needed five stitches for his head wound and was detained in the hospital.

Reporters inquired about the event at the daily police press conference on Tuesday, asking what remarks by the man broke the law and lead to him being arrested. Bradley Wright, district commander of Mong Kok, said police actions were based on the rule of law and evidence.

When asked if citizens would be taken away by police for simply shouting at them, Wright said no one would be arrested for expressing a view. But, he did not say what the Chu had actually done to break the law.

After further questioning, Wright said they would investigate whether the man had committed other offenses such as “disorder in public places”.

People say there have been other cases like this. Shatin district councilor Raymond Li was arrested on Sunday in Tai Wai in the New Territories after shouting at a group of police outside the MTR station: “Black cops who brutally beat up citizens are despicable.”

Anson Wong Yu-yat, a human rights lawyer, said charges of ‘disorder in a public place’ could not be tied to the sort of remarks these men appear to have been arrested for, news website HKCNEW.com reported.

Under Public Order Ordinance 17B, any person who in any public place behaves in a noisy or disorderly manner with the intent to provoke a breach of the peace, or whereby a breach of the peace is likely to be caused, shall be guilty of an offense.

Wong explained that the law did not focus on individual behavior. The focus should be behavior that has an intention to provoke a breach of the peace.

He didn’t think the words these men shouted actually broke the law of ‘disorder in a public place’.