...killed my daughter's rabbit.

I was at work, little one was with her dad. He was playing XBox in the living room while she played in her room. (She's 4) Well, she was not in her room, but the spare room where the rabbit cage was. LO let the rabbit out and then apparently the dog came in the room and snapped the rabbit's neck - in front of my daughter. She left the room to tell her dad that "the rabbit died" and he came in and saw that the rabbits head was facing the opposite direction it should be. The dog is standing there as proud as can be. Her dad is freaking out, she goes and gets grandpa who is fixing our fence and grandpa comes in and takes care of the situation. LO is talking about it A LOT but her preK teacher says that's normal and she's going to be fine. (I would not be fine. :-|)

Anyway, the dog is a female black lab. She is about 20 months old. We got her on April 5th of this year. We don't know a lot about her. She was a rescue. Should I keep her? I don't know what to do!