I'm far from an expert, but if she is always peeing or defecating in the exact smae spot, trying putting a gate up to block the area or close doors while gone. It sounds like seperation anxiety to me, assuming you are correct that only when alone does she become this other animal. Destructive behavior is a good sign, as is the constant peeing while you aren't at home. Personally, this is yet another reason why I feel strongly about crate training. But as for now, it can never hurt to see a vet. If while on calming medication the activities still persist, perhaps there are other issues at hand.