Pentagon police say a Kentucky man with a shotgun arrived at the government facility last week and told officers he had driven through the night to attend to "liberty business" there.
WTOP-FM reports Charles Lawson was arrested and charged with unlawfully possessing a firearm after previously having been committed to a mental institution.
Court records say Lawson arrived the afternoon of Aug. 6, approached two Pentagon police officers and made incoherent statements. It says police then questioned Lawson, who disclosed that had weapons in his car. Police searched his car and found a loaded 12-gauge shotgun, an 18-inch machete and a box of shotgun shells.
Lawson was hospitalized, and a doctor told police that Lawson mentioned he was previously diagnosed with schizophrenia.