I think i'm pretty close actually...
The religious connotation in this song is supposed to convey the power they feel when they kill and live out the violent sadistic fantasies in their heads.
Here are some quotes from this site:
www.crimelibrary.com
"The murders reflect a need to sadistically dominate the victim"
"The victim may have "symbolic" value for the killer; method of killing may reveal this meaning;"
"Serial killers are sadists, seeking perverse pleasure in torturing the victim"
"They need to dominate, control, and "own" the person"
"Some serial killers are precociously demented, fascinated by sadistic violence at a very early age."
"all they know are their fantasies of domination and control. They have not developed compassion for others. Instead, humans become flattened-out symbols for them to enact their violent fantasies."
"sex is linked to death, not life, for the lust murderer"
"to sustain the fantasy, serial killers come to a point where they need to live it out. They will dwell on the murder act for years, and drift into almost trance-like states days before the murder, completely enraptured by their fantasy."
"the brutal, messy reality of murder never completely fulfills the power of the fantasy. In fact, it is usually a letdown, but the fantasy won't go away — it is too deeply ingrained in the killer's psyche. This accounts for the serial nature of lust murder."
You can't tell me, after reading that, that what is in their heads isn't dark. No, they don't view it that way themselves. They can kill you without a care. The reason they do it though, is very dark. To live out disturbing fantasies of violence against other people.
All the quotes come from this article:
http://www.crimelibrary.com/serial_k...victims_1.html