Luo, 70, died from a blow to the head.
Local media reported at the time that he had been filming a fight between the two sides on his mobile phone.
On Wednesday police said they had charged two boys, aged 16 and 17, for his murder.
"The two were jointly charged with murder, wounding with intent and rioting," a police spokesman told reporters.
Even though they are minors, the teens face up to life in prison if convicted.
Hong Kong's protests were sparked by an attempt to allow extradition to China's opaque justice system but soon morphed into a popular revolt against Beijing's rule.
Millions of people took to the streets to protest for greater democratic rights and the demonstrations had often ended with violent clashes between protesters and police.
Fights often broke out between protesters and groups of government loyalists, with beatings and street brawls common.
More than 7,800 people have been arrested -- nearly 40 percent of them were students.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)
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