Kelvin Lau, 19, and Chan Yin-ting, 18, were earlier acquitted of manslaughter and wounding with intent over the incident outside North District Town Hall on November 13, 2019, which also saw another man suffer an eye injury.

Luo Chang-qing, a 70-year-old cleaner, died from a blow to the head during the confrontation between protesters and government loyalists when both sides were hurling bricks.

Judge Esther Toh Lye-ping said while Lau and Chan shouldn't be punished for the charges they were cleared of, that doesn't lessen the seriousness and tragic consequence of the riot and a deterrent sentence was required.

"Things devolved into mayhem which led to very tragic consequences," the judge said.

Toh adopted a starting point of six years and deducted half a year after considering that the duo lacked proper adult supervision and didn't foresee the disastrous consequences of their actions.

The judge also noted that the pair were remorseful for what they had done.

Earlier media accounts of the Sheung Shui conflict placed blame on both sides, but the judge praised the government loyalists as "unsung heroes" who acted selflessly and courageously when they stood up to the protesters.

The judge also commended the police for being "Asia's finest" and conducting a thorough investigation into the case.

At trial, defence lawyers argued that the duo were threatened by police to admit responsibility for the death.

In court, police officers denied allegations of coercion or intimidation.