Amanda says she’s convinced her father, who had pulmonary fibrosis, was murdered while he was in the hospital – despite an autopsy that determined he died of natural causes -- and she says she won’t stop fighting until she gets justice for him.

TELL DR. PHIL YOUR STORY: I'm Living A Nightmare!

“What I really do believe is that they were sick of him being adamant about what the treatment plan that he wanted was. If you give somebody something that is against their will, and they die from it, then you are in essence murdering them, and that’s what I believe,” she tells Dr. Phil on Tuesday’s episode.

“This is a serious allegation, because what you’re saying is if you annoy the staff, they kill you,” Dr. Phil says.

WATCH: Woman Who Claims Circumstances Surrounding Dad's Death Are Suspicious: 'I Won’t Stop Fighting For My Father Until I Get All The Answers'

“I believe that that’s what happened in my dad’s case,” Amanda says, claiming that a letter she found in her father’s Book of Mormon backs up her theory.

In the video above, hear what she claims her father wrote in that letter. Does Amanda have a case? See what a cardiologist has to say about her father’s health and death on Tuesday’s episode. Check here to see where you can watch.

TELL DR. PHIL YOUR STORY: Is Dr. Phil your only hope?

Man Says Sister Has 'Put Herself In A Perpetual State Of Re-Living My Dad’s Death'