Perseverance of the Saints
Big deal the guy was an athiest it's not relevant the guy killing 12 people is what's relevant.
Im fairly certain next week he will believe he's Joan of Arc. Followed by Charlemagne. After that Mario Williams.
The guys personal belief system had very little to do with his massacre. What it had to do with is his medical condition. He was a nutjob who, for whatever reason, couldnt get adequate treatment. The treatment he was receiving clearly wasnt working.
Of course, if he was a Christian, he wasn't really one. He was a cultural Christian, not a real one. This is a simple explanation for every Christian who does a bad thing. They weren't really Christians, despite actually reading and following the bible, they aren't real Christians.
This is a much more plausible explanation than he was simply a sick man. Gotta learn your stuff my friend...