Harassing postal customers by mail is a serious offense that should be reported to the authorities. Report harassing or threatening mail to the U.S. Postal Inspection Office website, call 1-800-ASK-USPS, and contact your local law enforcement officials immediately to tell them about the problem. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.