Trying to find out the name of a movie that came out in the 70s, help?

a girl went to live in a big house. a bad guy comes into the house the girl hides in a large dollhouse. there's a crazy wild girl chained by ankle in the attick. at the end the house catches on fire and an old lady unchains the wild girl. she acts like she is going to leave the burning house then runs into the attic with the wild girl saying it's better this way and locks the door. lead female escapes, bad guy dies, old lady and wild girl perish in the fire. does anyone know this movie?