Confused And Trying To Forgive

I came home last week to find one of my 9 month old kittens dead (Ziva)...killed by my own dogs. These are dogs that have lived with cats their whole lives (12 years) and have gotten along fine with the two new kittens that have been living here for 7 months. My other kitten, Frito was curled up with the dogs as if nothing happened.
I can't seem to wrap my head around what might have happened and I am having a hard time forgiving the dogs for their actions.
I feel guilty for not seeing any signs. I did keep a baby gate up when I was not home so that the dogs could not run the whole house as the cats did. Now I am terrified for Frito, even though he appears to be getting along with the dogs just fine. When I leave the house, I put him in the spare bedroom for his safety. He hates it and has been tearing up my carpet trying to get out.
I miss Ziva so much and I can't get that picture out of my head, nor do I look at my dogs the same way.
Has anyone experienced anything like this?? How have you coped with both the loss and the fact that your own "family" did it.

Dee