For four years, Ciudad Juárez on the border with Texas was convulsed by daily slaughter, becoming the murder capital of the world and a shocking illustration of the Mexican government's failure to contain violence among warring drug cartels. A number of drug war experts say security has also improved because the Sinaloa Cartel of Joaquin "Shorty" Guzman now has a firm hold on the city after squeezing out the Juarez Cartel, for long aligned with the local police.