Transcript for Police investigation leads to shocking discovery: Part 10
Today the rexburg police department conducted a search warrant at the residence of a Chad daybell. I wanted to kind of go through what happened on June 9th. That search warrant was executed at Chad daybell's house. What did they find? The FBI, they gridded off these areas, and they start peeling away layers. This is how you do this. You just don't start digging. It's almost like an archaeological dig to a certain extent. They removed some top soil that was right underneath the sod which revealed three large white rocks. Underneath the white rocks was some thin wood paneling. As soon as they removed the paneling I could smell the odor of a decomposing body. It was a -- what appeared to be a small body tightly wrapped in black plastic covered in duct tape. The investigator immediately recognized that that well could be j.j.'s hair. So, then you move onto another section of the property where the FBI's digging. Again, I think partly based on and they start finding charred remains. And they did exactly the right thing -- and the FBI will typically do this -- is they bring a forensic anthropologist with them to the scene. There was a melted green bucket that appeared the burnt flesh had been placed in. Under the bucket was a partial human skull. Human remains that were later I.d.'d through dental records that they matched tylee. And incredibly, while all this digging is going on, Ryan, Chad daybell is there initially. While the search effort is happening, he's actually there watching it in real time on the driveway, in his car. And, according to police reports, he's just sort of there continuously, the whole time, watching it happen. Then at one point, he moves the car across the street to his daughter's property. Watches from there. And then, once the remains are found, he decides that's a good time to go for a drive. And literally pulls off and starts driving. Obviously, police think otherwise, and they pull him over and arrest him. But when you think about it, this is all happening in real time. And he is sitting there watching it happen and then leaves as the remains are found. You have to think those investigators were, like, well, two and two equals four here. We know why he's leaving. I don't think he has any emotional connection at all to what they were doing in the backyard. I think he's thinking, I'm in I got get out of here. I got to run. I got to do something. I feel remorse. I feel emotion. Yeah, but anti-social personalities don't think through all that because they don't have any guilt. You know, it's, like, he thinks he's slick. And that basically, okay, you found these bodies here. Now prove that I killed them. And that's where we are at this point. How sure were they at that point that when they went digging, they were going to find those children? I think they thought they were on the money. And another reason is I think they had totally exhausted that these kids were someplace else. They clearly were not with the grandparents in Louisiana. They clearly were not with friends in Arizona or in another location in Idaho. And that this just made the most sense because, let's face it, Chad and Lori both have basically tried to snow the police. You know, deny, deny, deny. And then come up with all these, in my view, ridiculous stories. Like tylee is at BYU Idaho. I mean, you can check that in five minutes, you're from law enforcement. It shows you sort of the unsophistication, the perhaps arrogance on their part that they think they could pull this off. I'm curious because you talk about Chad and his anti-social behavior. That's one person. Now you have Lori capable of being a part of this and Alex as well. How unusual is it that you would have three people capable of doing something that is unthinkable to almost every human being when it comes to children especially? They take on this attitude that, we're superior to everybody else, and we live in a different reality, and the world's going to change. They think the world's going to end and there's going to be a second coming and they're going to be the king and queen of England after the rest of us it's such a bizarre, such a high-risk thing to do. Do you see murder charges coming? I'm surprised they haven't come. I think, the juries are gonna look at these two and say, you two are the zombies, not these kids. The only issue I have with that is prosecutors bring cases that they think in good faith that they can prove. So even if everything looks like a murder charge, they're not going to bring it unless they think they can prove it. The biggest mystery in this case is, who did it? If you believe that one of these three people killed these children, who killed which child? How did they actually do it? So if you have Chad and Lori right there, will you be able to prove to the jury that Chad definitively killed tylee? Not Lori, not Alec, did Chad do it? Or did Lori do it? Or did Alex do it? That I think could set up some problems for the prosecutors. So while I think there could be murder charges in the future, I wonder if they're looking for something more right now to try to figure out, how can I pin this on that person based on the evidence I have? If you lay out all of this behavior we've talked about today, I will tell you, working homicide cases for 30 years, it's pretty darn compelling. So, what's Lori doing as investigators are digging up Chad's backyard? She's picking up the phone.
This transcript has been automatically generated and may not be 100% accurate.