Over a half-dozen suspicious packages containing explosive materials have been sent to military installations around Washington, DC.
The Federal Bureau of Investigation (FBI) launched an investigation after reports emerged that the packages had been mailed on Monday.
Fort Belvoir in Virginia and Fort McNair in Washington each received a suspicious package.
The one sent to the National Defense University at Fort McNair tested positive for black powder and residue while it had a fuse attached to it.
The box sent to Fort Belvoir was reportedly rendered safe as well.
FBI authorities do not believe the packages had anything to do with the man responsible for a series of recent bombings in Austin, Texas.
Identified last week as Mark Anthony Conditt, the 24-year-old was responsible for a series of package explosions in recent weeks, which left two people dead and several others injured.
He killed himself as he was in his vehicle just before being captured by police.