DOJ: Packages sent by delivery services such as FedEx are suspicious because drug traffickers know the police can't open them without a search warrant. 
Therefore, federal taskforces hang out at shipping facilities such as the @FedEx hub in Indianapolis, where they pull suspicious packages off the line and have a drug dog sniff them (without warrants).
The drug dog's alert is often all the evidence the police need to seize whatever money they find. (They make no secret about the fact that this is an operation intended to discover cash, not drugs. It's in the government's court filing.)
(Which is interesting because people have known for a decade that a huge percentage of U.S. currency has at least some drug contamination. E.g., cnn.com/2009/HEALTH/08…)
What makes a package suspicious? A non-exhaustive list:
* The box is new
* Too much tape
* The sender paid with cash for overnight delivery
* A handwritten label
* Not sent to or from a business
* Destined for California
* The box is new
* Too much tape
* The sender paid with cash for overnight delivery
* A handwritten label
* Not sent to or from a business
* Destined for California
Here's the filing: documentcloud.org/documents/4770…
