This is what Mexican authorities say was a massive drug lab hidden in the woods. You can see rows of canisters, bags, and ovens. A rare look inside a secret meth lab in northern Mexico.But tonight, what happened after the law enforcement operation is raising questions about US involvement in the crackdown. A source with knowledge of the matter tells NBC News two CIA officers, along with two Mexican officials, died following the operation this weekend in a car accident. Mexico's President Claudia Sheinbaum i ...