Very interesting article about the process that LE uses to pull suspicious packages from the USPS mail stream for inspection and the standards for probable cause: http://www.oregonlive.com/portland/index.ssf/2015/05/portland_police_practice_of_pu.html#incart_m-rpt-1
Here's the link to the Court of Appeals case: http://www.publications.ojd.state.or.us/docs/A153361.pdf
Excerpts:
A U.S. postal inspector and Portland police had no legal authority to intercept a package headed to a Southeast Portland home just because they had a hunch it contained contraband and a police dog later alerted to it, the Oregon Court of Appeals ruled Wednesday.
Barnthouse, then 26, was arrested and booked into the downtown Multnomah County jail in April 2012 after police pulled a package from the mail stream that had been headed for delivery to his home near Southeast 36th and Belmont Street.
Although the package might have seemed innocuous to the average person, it set off red flags for police officers regularly stationed at the postal cargo center. According to the appeals court's summary of the case:
•It was addressed to a pseudonym "Maxi-pad Barnt" -- similar to Barnthouse's name. Police said that senders and recipients associated with the drug world often hide their identities behind fictitious names.
•It was sent from a state where medical marijuana isn't legal -- Delaware -- to a state where medical marijuana is legal and the drug is more prevalent -- Oregon. Authorities say marijuana buyers often send money to Oregon and get marijuana in return.
•The address was handwritten, not typed.
•The sender's listed ZIP code was different from the ZIP code from where the package was sent.
•The postage was paid with cash or debit card, not from an established business account.
That was enough, police said, for them to remove Barnthouse's package from the mail stream about 6 a.m. and set it aside for the narcotics-detection police dog, Nikko, to sniff. The dog signaled that something of interest was inside the package.
Pulling packages for the sniff test is something police and a postal inspector do 30 to 40 times per day, according to the appeals court summary. The dog is correct about 90 percent of the time, an officer testified. Officers typically end up investigating seven to 14 of the pulled packages a day by using their computer databases to search the names and addresses on them to see if they're linked to known criminals, according to the summary.
Multnomah County Circuit Judge Christopher Marshall agreed, finding that the first misstep by police was physically removing the package from the mail stream when they had no reasonable suspicion or probable cause.
Prosecutors brought the case to the Court of Appeals -- arguing that police hadn't actually "seized" the package -- that Barnthouse had no "possessory interests" in the package -- because officers brought the package to his home hours before its guaranteed delivery time of noon.
The appeals court disagreed Wednesday by upholding the lower court's decision.
"We conclude that, for an in-transit USPS express mail package, the police may not detain such a package without probable cause and a warrant or without the existence of one of the carefully delineated exceptions to the warrant requirement," the appeals court wrote.
The case against Barnthouse is now essentially over. Prosecutors have no evidence to proceed.
I would HIGHLY suggest anyone interested in the topic should read the court opinion I linked above, and especially the first 12 pages, which lay out a lot of the procedures which US postal inspectors and LE go through in identifying suspicious packages.
Here's the relevant paragraph:
They look for packages bearing exterior indicators that they deem characteristic of illegal-drug or drug-money parcels. Such indicators include the “overtaping” of a package’s seams; handwritten, as opposed to printed, shipping information; delivery from an individual to an individual, rather than to or from a business entity; variation between the zip code from which a package was sent and the zip code listed for the return address; payment for delivery by cash or debit card, instead of billing to a business account; origination from a non-medical-marijuana state; waiver of any signature requirement at delivery; and use of possibly fictitious or incomplete identifying information for the sender or recipient. Helton testified that it is common for the public to send express mail packages using handwritten labels and for people, including himself, to use cash to pay their fee.