(NewsNation) — Idaho stabbing suspect Bryan Kohberger has not yet entered a plea but prosecutors are already saying he will not be able to use the not guilty by reason of insanity plea.

During an appearance on NewsNation’s “Prime,” Former CIA and FBI agent Tracy Walder discussed how the insanity defense has not been available in Idaho since 1982.

“He actually cannot use it in Idaho,” Walder said. “I think we’re so used to hearing about it, because many states do allow it. And in this case, you know, I think his mental state may mean something to the defense. However, they can’t use it in a plea. And we have to be, you know, really careful with that. Because just because you may suffer from a mental illness of some sort doesn’t make one a murderer.”

Watch the full interview in the video player at the top of the page.