I suspect this fellow was still a theist.
Well, he reportedly shouted "Liars! Liars!" and shot the pastor. Okay, actually he was apparently referring to some secondary altercation that lead to the police investigating him for child molestation of a 14-year old girl. There's nothing to suggest even remotely that he lost his faith.
I would take bets to that effect.
I think I would have won.
Sadly, I'd even go far as assume religion played a roll.
Still no evidence here. Seemed to be a family matter in a small community where he had issues with the family of another church family. That doesn't sound like actual religious cause to me. The Police aren't helping to provide evidence for my speculation.
Also at some point he reported grabbed somebody, asked if anybody else would like to be killed in his stead, and then as nobody stepped forward shot the man. Somehow this seems pretty much an obvious result, perhaps he should have offered a leg shot vs. a headshot or something people could have said 'yes' to.