The true enemy is behind this. (Ephesians 6:10-13) The shooter isn't the real enemy here. The powers behind his evil deed are.
The shooter could have done this on a Sunday morning when there was a much bigger crowd. He could have killed more people and made a bigger headline. Why did he seemingly go small and murder the few in a prayer meeting of about 13?
I believe he was sent to go after those battling the true enemy on their knees. Our enemy knows where the battle is fought and won.