scared pitbull and a dead cat.

Question
I have a 5yr old American pitbull unspayed that I rescued from an abusive home a month and a half ago and last night  me and my spouse had a small gig to play so we left them home for a couple hours and I came home to my cat dead on the livingroom floor and my dog cowering. My cat has never really liked the dog and would Swat at the dog if she got too close to her but the dog would lower her head and walk away. She was teased with a cat at her former home and they threw the cat at her face and she did kill it. My questions are, should I have seen this coming and what should I do with this dog. She's become a part of my family and I don't want to get rid of her but I'm concerned she's a danger to me now... I'm even scared to go home because well for one I'm traumatized, and 2 I don't want her to attack me or my spouse. Please help me. Thank you!

Answer
Hi, yes you should have seen this coming.  Let me give you a scenario:
If someone poked at you with a sharp stick day after day and one day they went out and left the stick on the floor, would you try to get rid of the stick?  Yes, same thing.  She viewed the cat as something she feared when an adult was handling it and as soon as she had a chance to get rid of it, she did.
Is she loving toward you?  Does she cower away from you?  If you are going to be afraid, this dog is not for you, but if you go to a trainer and overcome the fear and learn how to handle her, you will learn from the trainer if she is a danger to you or not.  My guess, and it is a guess only because I cannot see the dog, is that she needs you to be the alpha.  You become that by training her to sit before you feed her and she can't go out a door without you going first then telling her to come. She needs to learn sit, stay, down, come, and "leave it" when you command it.
I would read up on the breed, they love people (usually) but are not great with other animals unless they have been trained to like them as a pup.  She was trained to hate them, but it is obvious the cat must have swatted at her and if she was hurt (scratched) and she retaliated.
I would go to a trainer that specializes in this breed, once you understand her signals, you will be able to make a better judgement on whether to keep her or not.
nancy