S1·E7 Who Killed Sweet Betsy?

Betsy Richards drinks a lethal martini and Burke investigates the Richards mansion, Betsy's three identical sisters (who may look alike, but who have decidedly different personalities), her wheelchair-bound (and possibly psychotic) aunt, her current beach bum lover (who might have been about to leave Betsy for another sister), her alcoholic brother-in-law, and a slightly demented professor of psychiatry. An attempt is made on the life of another sister and, after a second death, the dark secret of the Richards family is finally revealed.