Using this method, the existence of matched layers between confiscated packages from different regions over a 1,000 km distance showed an obvious relationship between the methamphetamine that had been illegally transferred on the open sea (region I), unloaded at region 2, and delivered to the mainland (region 3). This smuggling route was presumed to be controlled by organized crime in Japan. After a few months of investigation by the police, this route of illegal import and delivery was identified and inactivated. Polymer sheet layers of 29 individual packages used for packaging methamphetamine were retrieved from the 3 different regions in Japan. Each region was located over a 1,000- km distance and included the public sea. In Japan, there are many different colorless polyethylene (PE) and polyethylene/polyvinylacetate (PE/EVA) manufacturing companies. Therefore, there is a large supply of PE and PE/EVA films available, and the roller that is used to prepare the film is replaced frequently. A comparison of striation lines of polymer sheet layers and heat sealer marks was used to determine whether there was a common origin. Although there were no polymer sheet layers that showed similar striation lines in packages from all three regions, there were some polymer sheet layers that showed similar striation lines retrieved from regions 1 and 2 and regions 2 and 3. 5 tables, 9 figures, and 13 references