Officials say the suspect, who has not been identified, was taken into custody Wednesday night.
Surveillance video of the woman was recorded last week at a home near Hayden Road and Loop 101 in north Scottsdale.
It shows the suspect, wearing a USPS mail carrier shirt, walking up to the door carrying a box the homeowner said was empty. She dropped off the box and left with two packages belonging to the homeowner.
ABC15 reached out to the Postal Service for comment and learned the woman was not a real mail carrier. A U.S. postal inspector told ABC15 that simply wearing the postal shirt will exponentially add to her crime spree.
"I do believe this is someone impersonating a postal employee, which itself is a federal offense, in addition to the mail theft," said Postal Inspector Liz Davis. "We have not seen a lot of this in recent years. It's the first time I've even seen it this year at all."