David Koresh is responsible for the death of 54 adults and 28 children.
Michael Bray conspired to bomb abortion clinics in Washington DC and Maryland.
Matthew Hale attempted to solicit the murder of a Judge.
Paul Jennings Hill was an ordained minister who went to an abortion clinic in Pensacola and MURDERED a doctor and his bodyguard POINT BLANK RANGE.
Jim Jones is known for the mass suicide of 909 people including over 200 children. All of these people were forced to ingest cyanide.
All of these men...Christians.
The point of your OP was to point the finger at an Atheist. I am not defending James Holmes at all. But I am defending the Atheist community. You can't tell me that the Atheist community is bad because of one crazy person. Crazy people reside in all communities.
Are you seriously wanting to play the "who has killed more people" game? You're going to have a tough time surpassing Joseph Stalin's 50 million people if that's the case.