Nairobi, Kenya - An anti-police demonstration sparked by the police killings of a student and two human rights activists turned into a riot in the Kenyan capital. Thousands of youth, who have faced a rising tide of police violence in "anti-gang" crackdowns in recent years, built barricades, beat up journalists, pelted police with stones and looted businesses. Witnesses said a rally of about 2,000 students more than doubled in size as slum dwellers, jobless and others joined in.