A Florida man previously declared "criminally insane" was arrested after police found 36 guns and 4,269 rounds of ammo in his green Honda van.

David Harris Dunaway was pulled over for speeding on Saturday. During the traffic stop, Alachua County deputies learned that Dunaway was already wanted on weapons-related charges, according to the Tampa Bay Times.

The 58-year-old suspect had received an indictment in Tampa Dec. 18 alleging he had a pistol and 50 rounds of ammunition; because of his mental health, Dunaway is not allowed to own firearms. But police were about to uncover a veritable arsenal.

Deputies found 36 guns and 4,629 rounds of ammunition during a search of Dunway's vehicle, according to Raw Story.

Dunaway told the arresting officers that he was on his way to a flea market to sell some of his collection, but police did not believe his story. Dunaway was arrested and booked into Alachua County Jail, then later transferred to the custody of U.S. Marshals.

In 1992, Dunaway drove his car into a ditch. When trucker Leonard Allen Brower declined to give him a ride, Dunaway shot him point blank with an automatic weapon, the Gainesville Sun reported at the time.

After being examined by two psychiatrists, Dunaway was judged not guilty by reason of insanity and sent for treatment at the state mental hospital in Chattahoochee, Fla., the Daily Commercial reported.

It is unclear when Dunaway was released from the hospital, but the Bureau of Alcohol, Tobacco, Firearms and Explosives has been investigating him since last summer, when officials received a tip he was selling weapons, the Tampa Bay Times reported.