The sanctioned murders of alleged witches, including here in America, were not a form of human sacrifice, but were the result of nitwit superstitions, delusions, gullibility, unfounded fears, and the madness of crowds.
I think killing witches was more a form of enforcing law than a ritualistic killing (appeasing spirits or gods).
Various forms of execution would be a subject that could take a lot of grusome forms as well.