Hong Kong - Seven Hong Kong police officers were found guilty on Tuesday of assaulting a protester during pro-democracy rallies in 2014, in an attack that was captured on film and beamed around the world.All seven were found guilty of assault causing actual bodily harm to Civic Party activist Ken Tsang, but were found not guilty of a more serious charge of grievous bodily harm with intent.Video footage of the attack, filmed by a local network near the city's government headquarters, shocked residents and dented their faith in the usually trusted police force.It showed a group of men hauling a handcuffed Tsang to a dark corner in a public park, where he was beaten. One man stood over him inflicting blows while three others were seen repeatedly kicking him.WARNING: Not for sensitive viewers Police have been criticised for their sometimes heavy-handed treatment of protesters during the 79 days of rallies and street blockades which brought parts of the city to a standstill. The demonstrators were seeking fully free elections for Hong Kong's future leaders.Hong Kong's district court found that one officer had stamped on 40-year-old Tsang and that four other officers kicked him. Two other officers did not participate but watched. "Every police officer has a duty to prevent the commission of a crime, even by fellow police officers," a press summary of the verdict said.Judge David Dufton said in court that Tsang suffered injuries to his face, neck and body during the assault. "The court was not however satisfied these injuries amounted to grievous bodily harm but was satisfied they amounted to actual bodily harm," he said.The charge carries a maximum sentence of three years. Rival protesters gathered outside the court, with pro-police supporters outnumbering a small group of democracy demonstrators. Using loudspeakers they chanted: "Support the seven officers" and "Reasonable enforcement of the law".