Hong Kong police have arrested four boys on suspicion of inciting another person to become a member of an unlawful society and assault causing bodily harm, after a clip of a back-alley dispute in the early hours on Monday went viral. A police spokesman said on Wednesday that officers arrested four local boys aged 13 to 17 the day before, following an investigation based on a clip of a suspected attack in a back alley in Sai Wan Ho that had circulated online. “All arrestees are under custody for...