Old movie title (1930-1950 movie)?

There is an old movie, I dont have a lot of information, I saw it a month ago, and dont remember the name. All i can remember is how there was a young woman (niece or servant) and she lived with an older woman and she found out about a fortune in the fireplace and, there was something to do with a gentleman her age who got in on her idea to take the fortune. Thats all the information I can remember now.