A spokesperson for the law enforcement arm of the United States Postal Service says it is working as hard as it can to prevent people sending drugs through the mail to Guam.
Substance abuse is rife in the US territory and there is strong trade in methamphetamine, which commands prices up to 20 times greater than on the mainland.
Law enforcers welcomed last month's handing down of a 27-year sentence to the woman leading operation smuggling methamphetamine from the Philippines, citing it is as a mark of success in Guam's fight against drugs.
But Jeff Fitch of the US Postal Inspection Service says trying to stop people sending drugs through the mail is an ongoing battle.
"The real key is it's a crime against the United States to place drugs or the proceeds in the mail and because of that, we spend a lot of time working these cases. We have people specifically assigned and that's all they do. I would hate to be overly optimistic but we are, you know, it's a very concerted effort."
The US Postal Inspection Service's Jeff Fitch.