The exit to an underwater Mexican smuggling tunnel has been found in California, after a smuggler in scuba gear was found with 25kg of cocaine nearby.
Evelio Padilla pleaded guilty to one count of possession of drugs with intent to distribute at a San Diego federal court, a crime for which he could face up to 20 years in prison.
Border patrol agents found Padilla in a wet wetsuit near Calexico, California, a city on the Mexican border.
They also found a scuba tank fitted with a rebreather, to prevent bubbles rising to the surface, and the packages of cocaine.
This then led police to a 45 metre tunnel, which led to a house in Mexicali, just over the border in Mexico.
The drugs were transported down the tunnel via a trolley system, before divers retrieved it from under the water on the other side.
Attorney Laura Duffy said: "Drug smugglers will try anything to move their product - even scuba diving in an underwater tunnel."
"The ingenuity of the smuggler is matched only by our determination to thwart it."
Padilla claims that he had no other option, and was told he would be helping to get people across the border. Once he made it into the USA, he was forced into drug smuggling.
There are no details yet on whether any more arrests are expected, or on who built and maintained the tunnel.
South and Central American drug smugglers are resorting to extreme attempts to get their product into America, including via makeshift submarines and hidden under wigs.