Every last one of those people that were burned were innocent because witches are supernatural beings that use magic to harm others. No human in this world can do that. What would happen is something bad would happen to one person, then they would think it was because of another person, the suspicion would spread through a town or village. There would be mass hysteria in a village when things were going wrong.
I often wonder if I would become part of the mass hysteria if I lived in a village amoungst a person accused of being a witch in that time period. Would I help them build the fire? Would I believe the other people that are around me or would I be the guy that thinks it was nonsense? Would I be cheering as their hair melts and skin peels off? Would I be one of them? I don't know. I hope I would be the guy that thinks it is nonsense and doesn't get involved.