Police on The Take

Call him Gabriel. For eight years he was a consultant for the Direccion Federal de Seguridad, Mexico's internal-security police. Today he is one of the most articulate and useful informants on the drug-related corruption that has allegedly tainted Mexico's law-enforcement establishment. Gabriel overflows with stories of gunrunning, bribery, violence and death, much of it perpetrated by his old agency. Information provided by him has put U.S. investigators on the trail of major trafficking organizations abetted by corrupt Mexican officials. He recently met with TIME Correspondent Elaine Shannon to recount some of his adventures. "I was privileged to share in a lot...