Federal officials are not offering answers about their presence at a Rockingham County trucking firm.
Agents from the criminal investigations unit of the Internal Revenue Service spent much of Tuesday at Beam Brothers Trucking in Mount Crawford. They ordered cameras off the property, and pointed reporters to the U.S. attorney's office for information.
In a written statement, the prosecutor's office said it could not "confirm or deny the existence of an ongoing investigation."
Beam Brothers Trucking has been contracted to deliver U.S. mail for the past 18 years.
Reported by Tara Todd.