The body (spoiler alert)

I don't mean the father; I mean the young woman at the beginning who turns out to be Penelope Appleby. I've always been curious about who played her--was it Susan Strasberg in a (sort of) double role? This would explain why the face is obscured by dark hair after the body is pulled from the water.

There's a light (Over at the Frankenstein place)--The Rocky Horror Picture Show