Submarine could have carried up to 10 metric tons of cargo , DEA says . The $ 4 million vessel was built at a clandestine shipyard . Authorities found the sub hidden in marshland under triple-canopy jungle , Bergman told CNN 's `` American Morning '' program . ` Sub is first of its kind found by drug agents , DEA says . It is diesel - electric powered , the drug agency says .
Submarine could have carried up to 10 metric tons of cargo , DEA says . The $ 4 million vessel was built at a clandestine shipyard . Sub is first of its kind found by drug agents , DEA says . It is diesel - electric powered , the drug agency says .