1960s-1970s occult movie

I cannot find this movie and I can't remember the title of it and need help finding it. I had started watching it as a child and never got to finish it because my dad changed the channel after seeing what it was about. It had to be 1960s-1970s and I remember British accents. There is a rich old professor guy with a little blonde girl that is either his daughter or he's responsible for her and he's got all these occult books in his library and lives in a mansion and the little girl has a nanny and the nanny notices that the kid is weird like knows all the names of the trees and plants and tells her it from these books and she tries to bring it up to the dude and he brushes it off. It then it cuts to the kid stealing hair from the old guy from the bathroom sink after he shaves his face and then she makes a voodoo doll with it and kills him. It shows her making the doll and learning how to make it from the book.