A man brandishing a handgun walked into the North College Park Post Office and demanded money from the clerks Wednesday morning, marking the 13th robbery in Prince George’s County this month.

There were no customers in the post office, and no one was injured.

There were, however, three window clerks in the front of the office and a postmaster in the back of the building, and $35 in cash was stolen.

“He jumped over the counter line and took money from the open cash drawer,” Bob Martin, assistant postal inspector, said. He is in charge of investigating the robbery and was not present at the time of the robbery.

The suspect escaped in a “late model silver car,” and police do not have any suspects, Martin said.

Postal workers on scene said they were not allowed to comment on the robbery and referred all questions to Martin.

The post office, which is located in the 9500 block of Baltimore Avenue, was closed for the remainder of Wednesday. It was open yesterday for normal business hours.

Three hours before the robbery, the Cabin John post office in Montgomery County was robbed. It usually opens at 8:30 a.m. Martin said the two robberies are not thought to be connected.

The last U.S. post office robbery in the D.C. area occurred about a year and a half ago.

The U.S. Postal Inspection Service is primarily investigating the incident. The federal agency handles crimes specifically related to the Postal Service and is based in the D.C. area.

Martin said he encourages anyone with information to call the inspection service at (301) 345-8923.