Madrid, Spain (CNN) -- Spanish authorities have arrested 12 Britons on suspicion of drug trafficking in nightclubs on Spain's eastern Mediterranean coast and on the island of Ibiza, the country's Civil Guard said Monday.
The suspects include eight men and four women, and some of them are from Liverpool, England, the Civil Guard said in a statement.
Police searched six homes in eastern Alicante province, seizing five vehicles, one ship in the port of Torrevieja in Alicante province, and 53,000 so-called designer drug tablets. They also dismantled a marijuana plantation in the town of Creivillente, also in Alicante province, the statement said.
The police investigation into the group began in May.
Surveillance showed that the suspects regularly visited nightclubs -- often staying until closing time -- to sell drugs, the statement said. When supplies ran low, the suspects allegedly traveled to Britain to bring back drugs hidden in vehicles or in checked luggage on airplanes.
British police were deployed to Spain to assist the Civil Guard in the investigation.