Investigators say the vehicle belonged to an independent contractor.
That person picked up the mail from Philadelphia’s main post office.
“The property that was discarded on the sidewalk was only intended for a select number of businesses that have contracts with an independent courier, it’s not your average person’s mail,” U.S. Postal Inspector Alex Sylvester said.
Authorities say the thieves will face numerous charges, but since the mail was turned over to an independent contractor, it was no longer on federal property.