Murders, robberies drive up U.S. violent crime rate "More murders and robberies in 2006 sent U.S. violent crimes higher for the second straight year, the FBI said on Monday, with the increase blamed on gangs, youth violence, gun crimes and fewer police on beats." Internal disintegration Crime statistics tend to be rather unreliable. Still, the news is all the more sobbering in view of the fact that the US holds one of the world's largest prison populations.