Osiel Cárdenas Guillén — notorious drug lord nicknamed "Friend Killer" — returned to Mexico after U.S. prison sentence

Notorious drug lord Osiel Cárdenas Guillén has been returned to Mexico after serving a U.S. sentence and was quickly re-arrested and sent to a maximum security prison to face Mexican charges. 

There had been nervousness about the impending return of Cárdenas Guillén, who once led the feared Gulf cartel in northeastern Mexico before he was arrested and extradited to the United States in 2007.

The U.S. Homeland Security Department confirmed in its social media accounts Monday that Cárdenas Guillén had been returned after serving 14 years in U.S. custody, most of his 25-year U.S. prison sentence. He is a Mexican citizen, so presumably he was deported.