Do (most/some) LaVeyan Satanists believe in Satan?

I would say very few Satanists, who consider themselves to be LaVeyan, believe in Satan as a literal entity. If they do, they've got the wrong name; they're theists, or at least eclectic. Richard Ramirez is not a LaVeyan Satanist to my knowledge. But if he is, he is condemned by the Church of Satan because murder is never condoned. Any REAL Satanist, theistic or atheistic, would understand that Satan does not require one to commit crimes in his name. It is possible to "feel" Satan during our rituals, but in the context as Anton LaVey wrote; as an exteriorized extension of your own potential, as an alter-ego. I think the book you're reading is f-uped in general and you would have to quote specific verses for me to confirm.