Whether Dahlmer was an atheist or not has nothing to do with his crimes. One might as well say that Dahlmer being a Caucasian made him a cannibal.<quoted text>
Dahmer was an atheist, his killing was for his own desires.
"Despite the experts' disagreements upon whether Dahmer was sane or insane, they all essentially agreed that Dahmer suffered from major depressive disorder, generalized anxiety disorder, substance use disorder, sexual paraphilias, and borderline personality disorder."
( http://en.wikipedia.org/wiki/Jeffrey_Dahmer )