This is a rush transcript from "On the Record ," December 6, 2007. This copy may not be in its final form and may be updated.

GRETA VAN SUSTEREN, HOST: Well, warrant number four does show police are looking for biological materials in Sergeant Peterson's car, but what biological materials? Forensic expert Dr. Michael Baden joins us live in Las Vegas. Dr. Baden...

DR. MICHAEL BADEN, FORENSIC EXPERT: Hi, Greta.

VAN SUSTEREN: Good evening. We can all sort of assume what some of the biological material is, but let's sort of — like an investigator would, let's go through the list of what's likely they're looking for.

BADEN: Well, they're probably looking for evidence either of a struggle, or possibly, Greta, of a dismemberment. They'd be looking for blood, for hair, for broken fingernails, for even evidence of defecation or urination that might indicate something that happened as an individual died.

VAN SUSTEREN: All right. Let's talk about dismemberment. Now, she disappeared on October 28. We were there — that was a Sunday. We were there at least by Wednesday, and the police were going in with search warrants on that day. Had there been a dismemberment in the house or in the car, it's unlikely you could conceal that, would you agree?

BADEN: Well, it depends. Dismemberments are often in bathtubs, and it would depend on how thoroughly the police initially looked in the bathtub drainage. With somebody who knows what he's doing, if he was involved with it, if — if he were involved in such an enterprise, he would have knowledge of how to get rid of all of the biological evidence. And some of it may be in the vehicle, but if you find blood or hair, she had access to that while she was alive. So it's going to be a tough correlation, except it would help point in a certain direction.

VAN SUSTEREN: Well, it would certainly — it would certainly would take an enormous effort to accomplish that, especially with two sons in the house, one who is about 13...

BADEN: Right.

VAN SUSTEREN: ... and one who is 11, so — all right.

BADEN: Well, if...

VAN SUSTEREN: Go ahead.

BADEN: If a dead body — Greta, if a dead body were put into the vehicle, the hair from a dead body looks different than the hair from a live body. So that would be a real clue.

VAN SUSTEREN: Even, like, let's say that you had died an hour before and your hair ends up in the car, they can still tell a difference in...

BADEN: An hour is a little close. An hour is a little close. But after a few hours, it could, yes.

VAN SUSTEREN: It really looks that much different? So that let's say that someone's killed in the late morning and the body is moved about midnight. That's my hypothetical. You could tell a difference in a hair?

BADEN: Yes because as the scalp bacteria go into the hair, they cause a certain decomposition at the end of the hair in the scalp, that could be present after a few hours.

VAN SUSTEREN: Dr. Baden, thank you. Enjoy Vegas.

BADEN: Thank you, Greta.

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