Here are official propaganda posters from government agencies which they use to inform their employees about "suspicious" mail. These are, in some documents, referred to as "suspicious mail indicators."
According to USPS: USPS Suspicious Mail Alert Poster / alt hosted img 1 / alt hosted img 2
According to the US DHS/PIS/DOJ/FBI: Suspicious Mail Or Packages Poster / alt hosted img 1 alt link 2
According to the FBI: FBI Advisory on Suspicious Letters or Packages / alt hostedimg 1 / alt hosted img
According to the NSW Office of State Revenue in Australia: Suspicious Mail Indicators
According to some Canadian source: Suspicious Mail / [alt hosted img 1]https://anonimage.net/db/full/bOkHdUaVAe.jpg) / alt hosted img 2 These are almost the same as above.
According to SoBran Inc. (a company which provides "mail screening" service): Signs of Potentially Dangerous Mail / alt hosted img 1 / alt hosted img 2
They are pretty much all the same.
- No return address
- Wrong names or wrong title at correct address
- Misspelled names
- Handwritten labels
- Excessive postage
- Excessive tape
- Odors
- Stains or discolorations of packaging or envelopes
- Protruding wires
- "Lopsided or uneven"
- Rigid or bulky objects deforming the packaging
- Restrictive markings like "PERSONAL," "CONFIDENTIAL" or "PRIVATE"
- Mailed from a foreign country
- Mailed from a zip code which is not the zip code on the return address
All of these are considered together or just one could, by itself, draw attention to your piece of mail.
There are other signs of suspicious mail which I have seen quoted in criminal complaints, affidavits and court papers. One is:
- Mailed from a known drug source state
I've seen that in warrant affidavits for drug mail sent from California and Arizona. You can probably add to that list all the states which have legalized cannabis for adults.
Another two which have come up many times in criminal complaints are these:
- Wrong name used with an existing, actual return address
- Completely fake return address which does not actually exist
Further indicators of suspicious mail are the following, pulled from an article in The FBI Law Enforcement Bulletin published in 1996:
Postal inspectors use these criteria to identify packages that might contain drugs.
Package Criteria
- Emits odors of marijuana or or a masking agent (e.g., coffee, perfume, fabric-softener sheets)
- Is heavily taped along seams
- Is poorly prepared for mailing
- Appears to have been re-used
- Has an uneven weight distribution
Label Criteria
- Is handwritten
- Contains misspelled names, streets, or cities
- Originates from a drug source State
- Has been sent from an individual to an individual
- Contains return address ZIP code that does not match accepting post office ZIP code
- Shows a fictitious return address
- Lists sender's and/or receiver's names of common type (e.g., John Smith) that are not connected to either address
"ticking sounds"