The postal inspector's office says the man, caught on surveillance, walked into the post office armed with a device and announced a robbery.
Postal workers had just opened the office and were startled. The man fled with several hundred dollars in cash.
"It's very rare," said Postal Inspector Reggie Wade. "In fiscal year 2012, nationally there were 83 robberies. We had 53 arrests. We were able to prosecute 50 individuals. It's very rare and we want to keep it that way."
The Postal Service wants to add to that list and get Friday morning's robber off the street.
Investigators want you to take close look. He has a beard, was wearing a Phillies hat and what appears to be a surgical glove on one hand, likely to prevent fingerprints.
His alleged score was not much, but the reward for his capture is. It's $50,000.
Robbing a federal employee or institution is a federal crime. The penalties are severe.
"It's just not smart," said Wade, "just not smart. And we will find you and prosecute to the fullest extent of the law."
The suspect could face 25 years behind bars.
If you know that man or have information, call this number 877-876-2455. Your tip can remain confidential.