I have searched and searched for this online, but to no avail. I saw this movie as a child and it scared the daylights out of me. It was in black & white, and I'm guessing from the '40s or '50s (possibly very early '60s). As best I can remember, a young woman comes back to a house where she witnessed the murder of a family (while she hid under the bed in the attic?). She can't remember what she saw then but freaks out every time she goes upstairs to the attic and sees a white curtain blowing in front of the window. I think she's now engaged to the only remaining son of the family, and at one point, she's suspicious of him and he tells her to kill him and remove the curse on his family forever. If I recall correctly, it ends up being the caretaker or handyman who was the murderer.