Explosives have been found in the impounded pickup truck driven by the man discovered carrying a loaded shotgun on Capitol Hill last month, U.S. Capitol police told FOX News.

Michael Gorbey, 38, of Rapidian, Va was arrested in late January, and at the time police said there was a suspicious substance in his green pickup truck parked near the corner of North Capitol and D streets in Washington, D.C.

The truck was impounded at the Government Printing Office garage on Capitol Hill, not far from where the incident unfolded.

Police executed a search warrant Friday.

Kimberly Schneider, a police spokeswoman, said Gorbey could face additional charges.