I get a version of this question dozens of times every day, so let me just answer it in the most direct way I know how to:

I have never killed anyone, fictional or otherwise. I have no idea what it’s like to kill someone, but it seems like it would be horrible. One of my biggest goals in life is to get through it without knowing anything of what it’s like to kill another human being.

People die. That’s true in novels, and it’s true in life. Dying is one of the very few things we all do. To deny or ignore the omnipresent reality of death seems to me a disservice to human beings. That said, acknowledging in my novels that death exists does not make me a murderer any more than acknowledging that cancer can be treated makes me an oncologist.