Colombia ? Squat, bull-necked and sullen-looking, Enrique Portocarrero hardly seems a dashing character out of a Jules Verne science fiction novel.

But law enforcement officers here have dubbed him “Captain Nemo,” after the dark genius of “20,000 Leagues Under the Sea.” They say the 45-year-old designed and built as many as 20 fiberglass submarines, strange vessels with the look of sea creatures, for drug traffickers to haul cocaine from this area of southern Colombia to Mexico and Central America.

Capping a three-year investigation that involved U.S. and British counternarcotics agents, Colombia’s FBI equivalent, the Department of Administrative Security, arrested Portocarrero last month in the violent port city of Buenoventura, where police say he led a double life as a shrimp fisherman.

A day later, they swooped down on Portocarrero’s hidden “shipyard” in a mangrove swamp 20 miles south of here and destroyed two of the vessels, which police say were capable of carrying 8 tons of cocaine cargo each.