Where the truth lies. she concluded the most reasonable explanation for cory s arms appearing to levitate, is that cory was dead up to 12 hours before police arrived on the scene. i viewed this material and reviewed it with the eye of a scientist and and what we know about the development of rigor mortis. reporter: what would a jury believe, science, or the words from two of cory s own sons? cory s brother, a dentist, found himself struggling over the conflicting facts. science is my living you know, it s i have to believe in that, but i also have to, you know, believe in the family at the same time. so i m completely torn. reporter: i ve never seen a more difficult case, more closely argued. and there doesn t seem to be middle ground to there s there s none. reporter: parkinson urged the jury to focus on the science and one image. cory in her bed, her body in rigor mortis. he said it proved she d died hours before curtis claimed. it proved he was lying. it proved