Confessed Craigslist Killer -- TOO EVIL -- Even For Church of Satan

Confessed serial killer Miranda Barbour is giving Satan a bad name -- so says the high priest for the Church of Satan who says she's just too wicked.

TMZ broke the story ... Barbour confessed to committing between 22 and 100 murders ... saying she was compelled to kill by the devil after joining a cult in Alaska.

High Priest Peter H. Gilmore tells TMZ ... the official Church of Satan has never had any involvement with Barbour ... and would NEVER accept her as a member.

Gilmore tells TMZ ... true Satanists don't believe in murder (not even sacrifices) ... and if Barbour is truly a killer she should get the death penalty.

Gilmore says his church is not a cult but a legally recognized atheist organization ... adding Barbour is simply using Satan as justification for her crimes.