Not quite sure who Amazon is cooperating with, but it's certainly not us, as both Amazon and Postal Service officials refused to comment on the probe. Although there are quite a few specific mail no-nos that might spark such a probe—such as distribution of child pornography or narcotics or other illegal items—postal inspectors are a great catch-all federal law enforcement tool. Can't prove that a thief stole something? Charge him with mail fraud for shipping it to someone else. Or, the investigation could even be enforcement of a very old still-on-the-books law that—believe it or not—makes it a federal violation to use someone other than the U.S. Post Office when there is no business need for something to move through an alternative carrier, such as FedEx or DHL.
Amazon.com is quite familiar with federal investigations, but the world's largest E-tailer is not used to being the target. In a January 30 SEC 10-K filing, Amazon's government filing casually mentioned: "In January 2009, we learned that the United States Postal Service, including the Postal Service Office of Inspector General, is investigating our compliance with Postal Service rules, and we are cooperating."