Immediately come the stupid calls for gun control, before the facts are known.  There was gun control that would have prevented this sick and twisted individual from buying his guns.  Unfortunately, someone in government forgot to file the proper paperwork.  The man had assaulted his wife and stepchild, for which he received a dishonorable discharge, and for which he was supposed to be prevented from buying guns.  Gun control failed.
And the man was an atheist.  Actually, he was a rabid anti-religionists and a serious mental case.
He was confronted by other citizens, using their guns to force him to stop.  He then took his own life and has almost certainly discovered that Hell does indeed exist.