The US Postal Inspection Service.
Yes, although it isn't your fault the box got destroyed, it isn't the carriers either. Mail has to be delivered to a US Postal Service approved mail box They would be remiss in their duties if they just set it someplace. Carriers get payed and evaluated on the time for their work, which does not include dismounting the vehicle to deliver mail in some cases.
Dog the bounty hunter.
The NTSB (National Transportation Safety Board).
The services that the mail offers in the US are certified mail, registered mail, insured mail, express mail, and many more.
Yes, US mail should be capitalized as it is an abbreviation for United States mail.
Poirot Investigates has 310 pages.
Poirot Investigates was created in 1924-03.
No, US Postal Regulations prohibit the placing of anything but US Mail either in, or on, mail boxes.
The US Department of Justice
Lord Darcy Investigates was created in 1981.
BBC Scotland Investigates was created in 1993.
Paul Connolly Investigates was created in 2011.