Who is Osiel Cárdenas Guillén, dreaded drug lord known as ‘friend killer’
Osiel Cárdenas Guillén, the notorious drug lord and former leader of the Gulf Cartel, has returned to Mexico after serving a 14-year prison sentence in the United States, CBS News has reported. His return to Mexico is a significant moment in his criminal career, which spanned the trafficking of massive amounts of cocaine and marijuana…