An Indianapolis man was arrested in August for planning a domestic terrorist attack, Indiana police confirmed Monday.

The Greenwood Police Department arrested Christopher Byrne on August 15 after discovering he was driving around with a firearm, ammunition and chemical weapons.

An officer first spotted Byrne driving suspiciously around the Greenwood Park Mall parking lot and followed the car. The suspect was later pulled over for a traffic violation. Byrne refused to cooperate with the officer during the stop, explaining he was a "sovereign national."

Police eventually arrested Byrne as a "habitual traffic offender," according to CBS-4, though the Greenwood police have not confirmed the charge.

During a post-arrest search of the vehicle, police uncovered a scope and handmade suppressor attached to a Ruger 10-22 rifle, as well as 100 rounds of ammunition. Law enforcement also discovered water bottles containing bleach and ammonia in the back seat of the car — chemicals that when combined in the air or an enclosed area, form a toxic gas.

Local police have had previous run-ins with Byrne. In October 2014, Byrne stole an AR-15 rifle from a Greenwood officer's vehicle and lit her car on fire. Police eventually caught Byrne and found other stolen police items in his apartment.

It is unclear if Byrne had planned to attack people at the Greenwood mall on the day of his arrest, but the arrest came one week before Byrne had been due to appear in court to face a jury trial for previous charge. Officials are now considering additional charges for the Aug. 15 incident, including toxic chemicals charges. The suspect's previous bond has been revoked and his new bond stands at $1 million.