Spanish police arrested three men suspected of piloting a drug submarine carrying more than 3.6 tons of cocaine from South America to the Galicia region in northwest Spain.

Their wet clothes and claim that they were pilgrims walking the Camino de Santiago raised suspicions of a driver and a taxi driver, leading to their arrest.

Investigations began in August in cooperation with the U.S. Drug Enforcement Administration, after tracking a gang allegedly disguised as a marine equipment sales and repair company in the town of Outes, Galicia.

On September 13, police spotted high-speed boats belonging to the gang leaving the port of O Freixo, and teams were deployed to intercept them upon their return loaded with drugs from the semi-submersible submarine.

Upon the boats’ return and the gang’s attempt to transfer cocaine bales to two trailers, police intervened and seized one ton of drugs after one trailer overturned during a high-speed chase. The rest was found hidden under a tarp on a nearby beach the following day.

The alleged submarine crew, Colombians and Ecuadorians, tried to escape in a taxi with wet clothes, claiming to be pilgrims, but the taxi driver noticed their suspicious appearance. They were arrested after a diving suit was found in one of their bags. The submarine is believed to have crashed or been sunk miles off the coast of Galicia.

Alongside the seizure of 3.65 tons of cocaine, police arrested 14 people on charges of drug trafficking and belonging to a criminal organization, and confiscated 54,000 euros, two boats, five cars, and a trailer.

This operation highlights ongoing efforts to combat drug trafficking via drug submarines, which have become an increasingly used method to transport drugs across oceans.