Dog act: Colombian vet arrested after implanting bags of heroin in puppies Dog act ... Some of the puppies used by drug smugglers. A COLOMBIAN vet has been arrested for surgically implanting bags of liquid heroin inside puppies so the drugs could be smuggled into America. Police in Spain arrested Andres Lopez Elorza on an international warrant this week after eight years on the run, according to the UK's Daily Telegraph. Liquid heroin ... Drugs recovered in the 2005 raid. The 44-year-old is accused of being part of a ring that Colombian authorities busted in 2005. Six labrador and rottweiler puppies were discovered on a farm in Medellin during police raids. They were found to have had bags containing 400 grams of liquid heroin surgically implanted in their abdominal cavities. Three of them were due to fly to the US once their scars healed properly. When we gave the dogs an X-ray we did not detect anything. We did an ultrasound and there you could see the outline of the bags in their abdomens," said Medellin police chief Ruben Carillo at the time. We had never had a similar case for hiding drugs. He said three of the animals died during the process to remove the drugs. It was thought the trafficking ring had been using dogs as couriers between Colombia and the US for months before it was uncovered. Elorza was arrest in Lugo, in Spain's north-western region of Galicia on Tuesday. News of his capture comes months after a gang of South American drug dealers was caught sending 48 dogs to Milan that had been forced to swallow packages of cocaine. Customs is warning of a 'cocaine invasion' as drug smuggling syndicates learn sophisticated new tricks.