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WASHINGTON, D.C. (CBSMiami) —  FBI officials say they responded to multiple suspicious packages at military and government facilities around the nation’s capital Monday.

Police have arrested a person in Washington State in connection to the investigation.

A package sent to the  National Defense University at Fort McNair in Washington was flagged as suspicious during the normal screening process and the building was evacuated.

The package contained materials that tested positive for explosives, including black powder.  It also appeared to have a fuse attached.

Packages were also reported at a number of other mail facilities. One was addressed to the National Security Agency and another was stopped at the Secret Service mail facility.

All of the packages were rendered inert by disposal units at each base and sent to the FBI lab at Quantico, Virginia for examination.

The packages also included letters which a law enforcement source described to CBS News as “threatening” and “rambling.”

It was just a week ago that law enforcement officers tried to arrest 27-year-old Mark Anthony Conditt who blew himself up as they closed in on him. He was accused of delivering package bombs that killed two people and injured others in and around Austin, Texas.

The FBI does not believe the cases are related.

The suspect in the suspicious packages case is expected to make his first appearance in court later today in Washington State.