Reporter: Long after most of us put our work week behind us, kelly osborn is still up at night. Still pouring through every piece of evidence but by far the most difficult pieces to study --- are the...  Reporter: Long after most of us put our work week behind us, kelly osborn is still up at night. Still pouring through every piece of evidence but by far the most difficult pieces to study --- are the images of her dead daughter. A lot of people will ask, how could a mother look at the photographs from an autopsy? I don't recommend it to any, any parent. But why did you? I had to. I became my daughter's investigator. I didn't have a choice. Reporter: And immediately there were clues. The kind she says only a mother would notice. The first, I was very shocked at um, looking at her eyes. Sheena and i, we wore the same mascara, and I knew that we, if you cry with this mascara on, that mascara just clumps up, your eyelashes are all clumped up and, and hers were perfect. Reporter: If sheena took her own life, there were no tears, which experts say is very rare. Her make up untouched. Reporter: Something else only a mom would notice -- that diamond bracelet they fawned over at christmas. Reporter: Kelly says it was on the wrong wrist. It is on her right wrist, and I knew that sheena didn't wear her bracelets on her right wrist. As a matter of fact, that video on christmas, when she got that bracelet, she takes that bracelet out of the box, and shows it, with her right hand and automatically places it on her left wrist. Reporter: The crime scene photos also show both the bathroom and the shower doors left open. Sheena's mother convinced she would never have done that with her babies - her two little dogs right there in the room. She would have made sure that her dogs didn't see her that way. One or both of those doors would have been closed. Reporter: And while that's what a mother noticed from those photos veteran crime reporter lee williams saw something else. There's a photo of sheena in the shower, her feet are caked with sand and debris, yet there's no debris on the white floor, on the shower or on the white floor of the bathroom immediately outside the shower. So her feet were caked in sand and yet there was no sand anywhere in that bathroom? None whatsoever. Other than on her feet. Reporter: For williams, sand on her feet and not on the floor around her, makes it nearly impossible to believe sheena killed herself in that shower. So either sheena was carried in there, post mortem, and hung. Or she somehow levitated into that room. Reporter: Kelly had the reporter on her side, but what she truly needed were some big names, forensic heavyweights. And she got three of them to look at all the evidence. One of them taking 20/20 went back to that very hotel room with her. Reporter: Jan johnson is one of those c-s-i experts who examined the evidence. She's spent more than 40 years studying crime scenes, and she immediately saw red flags. A pillow lying on the floor. I would be interested in what is on that pillow. Reporter: A veteran investigator would rule everything out, asking could that pillow have been used to smother her. You're thinking someone could have used one of these pillows to kill her. Absolutely. Reporter: Most telling the bathroom. Where she says crucial evidence was missed. This is where sheena was found hanging from a dog leash. That's correct. It's attached to the shower head. Clipped at the top. Extending downward. The noose around her neck. Her buttocks eight inches off the ground. She's extended toward the back side of the shower with her legs extended outward. Reporter: She's not suspended in midair. No. Reporter: Her legs are on the bottom of the shower. Flat. Reporter: Wouldn't that give somebody ample opportunity to pull themselves back up? Absolutely. Reporter: She points to her clothes, if she were convulsing she would expect the clothes to ride up the body. She points to the cuffs of her pants down around her feet and january says it looks like she was dragged into the shower. The pants are her-- extended outward. And you would have expected if she had, you know, walked her way down the shower wall and hung herself that the pants would've gone up her legs. I mean, her clothing is perfect. She appeared serene, like she had just fallen asleep. A hanging is a violent act. Towards the end, um, your body fights that, it fights the ligature. It struggles to get air, and there was no evidence of any of that. Her hair was perfectly in place. Yeah. And in fact you described it as tucked right behind her ear the way she typically would. It was like a mannequin that had just been pushed over on its side. I've never seen a hanging like that. Reporter: And one more red flag for jan and that entire team of experts was what they saw in sheena's eyes. When you looked at those images and saw she had popped blood vessels you thought -- she had been strangled. You usually see petechial hemorrhages in a strangulation, you don't often see them in a hanging. Reporter: The hemorrhaging in sheena's eyes they believe is more consistent with a violent struggle, a strangling and then the bombshell conclusion. All three experts weighing in, and in every one of their reports -- three words stood out, "staged crime scene." And that's huge, that means that what was done to sheena was staged to make it appear as a suicide. What I think happened in that room that night is -- I think that she may have been suffocated on the bed and i think that she was dragged into the shower and placed into that leash that was already set up on that shower head.  This transcript has been automatically generated and may not be 100% accurate.
Act 3: A crime scene expert discovers 'red flags' in the hotel room Sheena Morris was found dead in.