US: DEA agent on bringing down the 'almost untouchable' El Chapo From 2012, DEA Special Agent Ray Donovan spearheaded the investigation of the Sinaloa cartel that resulted in the arrest of Mexican drug lord Joaquin "El Chapo" Guzman, who was sentenced to life in prison last week. Donovan, who worked from Virginia to coordinate efforts to track down Guzman in Mexico, says the Sinaloa cartel continues to control "the drug distribution markets in the United States."