Apparently he was the owner of a shooting school of some sort.The law changed to allow carrying in churches back on 1 Sep, so pretty recently. Scary to think what would've happened if that guy didn't have a gun.
And not to sound macabre, but the dude that put the shooter down dropped him with a headshot from 15-20 feet away in about 5 seconds after the shooter's first shot. Cool as a cucumber.