(KRON) — A United States Postal Service carrier was robbed of their postal keys in Oakland over the weekend, the U.S Postal Service confirmed to KRON4. The mail carrier was in the 3000 block of Linden Street in Oakland at around 6:50 p.m. when the robbery occurred on Saturday, Aug. 5.

The robber brandished a weapon and demanded the postal keys, Postal Inspector Matthew Norfleet said. The carrier surrendered the keys and was not injured.

There is a $50,000 standing reward for information leading to the arrest and conviction of the robber, or anyone else who robbed or threatened a postal carrier.

No other information has been released at this time.

The incident is the latest in a series of Bay Area robberies targeting postal workers. In most of the incidents, thieves targeted postal keys, which open up mailboxes.

“The postal keys have one legitimate purpose, which is to deliver the mail,” said Norfleet. “The only other thing you can do with them is steal mail.”