Sable in the Rain — W.E.D. Ross

Vivacious young Erica Blake and Bruce Cord were more than just casual friends. They had met at college and dated quite regularly. But suddenly Bruce vanished without a word, without a trace, and Erica had to know why. Finding out wouldn't be easy. The only clues to his disappearance lay behind the heavy stone walls of a strange impenetrable mansion called French House.

That's when Erica decided to become a secretary to the wealthy, enigmatic Belinda French. But from the moment she entered the woman's home she was struck by the ominous echoes of fear that seemed to haunt every room...echoes that became shrieks of terror as she found herself a hapless prisoner in a mansion of menace and evil.

Takes place in Harwich, Massachusetts