A construction worker was found guilty of three charges of assaulting police officers by whistling at them through his fingers during the annual July 1 protest march last year.
Magistrate Ho Wai-yang told Eastern Court yesterday that Ki Chun-kei's whistling was so loud and piercing it caused ringing in two auxiliary police officers' ears, while a third officer immediately had to take a step back.
Ho concluded that the action amounted to "use of force" and since it was not done in self defence, it constituted an "illegal use of force".
"Every Hongkonger has the right to take part in protests. The court respects that," Ho said.
"But the court does not allow the illegal use of force."
Ho said yesterday that she accepted the three officers' earlier testimonies to the court as they were clear and unanimous.
On one occasion, Ki, 50, had whistled into an officer's right ear from a range of less than a foot. The officer earlier told the court that it caused a ringing in his ear, leaving him unable to hear clearly for two to three seconds.
Ki was acquitted of two of the five charges because one officer's statement to police differed from the testimony given in court, while another officer was unable to identify whether it was really Ki who had whistled in his ear.
But Ho said she did not accept Ki's testimony that he was unaware the officers were nearby when he whistled.
Video footage clearly showed Ki approaching the officers and whistling at them for no reason, Ho said, adding that it was "impossible" he did not know that the officers were there, since they were wearing police uniforms.
"I do not accept that he did so unintentionally," Ho said.
In mitigation, lawyer Pauline Leung Po-lam said the whistling was not as serious as other police assault cases.
"There has been actual body contact in other cases. But in this case, it was just a short ringing in their ears," Leung said.
The lawyer suggested Ho apply a fine as punishment, but Ho said she "absolutely would not" since Ki had faced "similar charges" before.
Ho said she would wait to see one background, one psychological and two mental health reports for Ki before handing down the sentence on March 12.
Kwan King-pan, chief inspector of Hong Kong Island's regional crime unit, said that while the force respected freedom of assembly, no one should be allowed to provoke, attack or humiliate police officers.
Asked if the police would lay charges against anyone whistling at officers during protests in the future, he said it would be determined at the time, on a case-by-case basis.
Human Rights Monitor director Law Yuk-kai said that even if Ki had deliberately whistled in the officers' ears, he might not have intended to harm them.
In 2003, protester Sunny Leung Chun-wai was found guilty of assault and jailed for two months after he shouted through a megaphone into a police officer's ear.