That's basically implying she's asking anyway, but not going to answer. Well, Ellie can give her a half answer in that case.
"They were the FBI, according to their stupid ass coats. Anyway, do you need to ask? We had the same reason in the end. I wanted him dead! Gyhahaha!"
She throws back her head and laughs, bringing back some of the madness she had entered this prison with.
"Ain't it that simple? I made a choice. He would die! But, you know, folks like him make a lot of choices where people lose their lives everyday. I never see them goin' to prison for those. Pisses me off. I think people like that should walk with a little more fear in their steps."