So apparently there was nearly a mass shooting in my state:
Authorities in North Dakota say a man armed with 1,800 rounds of ammunition and explosives unleashed a “murderous barrage of fire” as he ambushed officers who were investigating a crash.
apnews.com
A guy named Mohammed had a ton of ammo and a grenade, along with every gun-grabber's favorite gun in his car, and he apparently came upon a traffic accident in town and waited for the responding police officers to group up before opening fire on them. He also shot a bystander who was trying to get away. As it happens, there was another officer there who was not in the group standing around talking and he was able to take this guy out. The thinking is that since there was a fair in town, this guy was hoping to do this, and then head over to the fair while the police were all swarming the scene of this shooting and trying to figure out what happened, which is why he tried to kill the bystander, too.
As I said, an AR-15 was used, apparently with American flag stickers and such on the magazines, and the FBI also just happened to be in town, and was involved when the police evacuated the apartment building this guy lived in and searched his apartment.