If they were truly witches and spiritists, then they weren't innocent. I believe the Salem witch trials were flawed trials. Giving a person a death penalty on the basis of no more evidence than two people's testimony is not an adequate trial. I don't know much about the European trials.
That's a religeous opinion--to those of us who wish the state would restrict itself to prosecuting tort crimes against person and property, it looks like you recruiting the state to do your religeous wet work.