Inside - Season 4 Episode 1 Inside Cocaine Submarines

Colombian drug traffickers are using a new secret weapon to smuggle cocaine north: drug submarines. Up to 100 feet long and nearly impossible to detect , they are capable of distributing several tons of coke in just one shipment. Dozens of subs are thought to be in operation between the coasts of Colombia and Mexico, and law enforcement estimates that another 70 will be built in the next year alone.