This is a book I saw in a used store a number of years ago. I can’t remember the title or the author and it’s driving me insane.
It’s from the early 80’s and appears to have been the work of a B List author. The cover depicts an altar boy in a robe, his mouth open and holding a songbook. Behind him an arm is reaching forth with a knife to his throat. The background from which it emerges is black and empty.
I vaguely recall the back blurb. Apparently it was a horror-murder mystery about the murder of an altar boy in a small English town and plays with the anti-semetic concept of a “blood libel” in a modern setting.