Gavin Long, shot by police after he killed three police officers and wounded others in Baton Rouge, had filed court papers in Missouri declaring himself a “sovereign citizen.”

This declaration of being ungoverned by law has a dark past in Arkansas. A father-son team of “sovereign citizens” killed two West Memphis officers after a traffic stop in 2010. They were killed, too, in the shootout.

At a press briefing today, Louisiana officials said Long came to Louisiana with a plan to do harm, though much remains unclear about his motives. He had been in Baton Rouge a few days and had “interacted” with people in the city, authorities said.