ORLANDO, Fla. -

It was Thursday, Dec. 11, 2008, and Chief Medical Examiner Dr. Jan Garavaglia was late for her plane.

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Then she got word that skeletal remains of a child had been found around the corner from the home of Casey Anthony, the young woman she knew had been indicted two months earlier in the death of Anthony?s missing 2-year-old daughter, Caylee.

Caylee was missing no more.

But, Garavaglia told Local 6 Thursday, she could not change her plans.

When she returned to her office Saturday, Dec. 13, Garavaglia took over the case from a relatively new hire, Dr. Garry Utz. ?I felt that Dr. Utz hadn?t been here that long and that I should go ahead and take it over,? she said.

So when Casey Anthony goes on trial in May, Dr. G. -- as she is known to viewers of a cable television series in which she stars -- will be the key witness who will tell jurors Caylee Anthony was the victim of homicide.

That?s just one of dozens of revelations uncovered by Local 6 in a review of hundreds of pages of depositions taken in the case of the State of Florida vs. Casey Anthony.

Anthony, 24, is charged with first-degree murder and aggravated child abuse in a case where the state is seeking the death penalty.

Local 6 has reviewed previously unreleased depositions of Garavaglia and others, revealing not only how prosecutors are preparing to use testimony to buttress their claim that Casey Anthony murdered her daughter, but also how the defense may challenge that testimony.

Garavaglia was questioned under oath in her Orange County offices for one hour, 19 minutes on Tuesday afternoon, Sept. 28, 2010.

Her primary interrogator: prominent defense attorney Cheney Mason, who -- at age 67 -- reminded Garavaglia at one point ?this is not my first rodeo.?

?Will you define homicide?? he asked.

?The death at the hands of another,? Garavaglia responded, then, when challenged, added, ?Forensically, hands or means ? I don?t know if hands -- maybe actions of another or neglect of another.?

Mason then suggests another possibility: ?Suppose this child drowned in the family swimming pool??

Whether that is a clue to a possible defense -- accidental death -- no one will say. The defense and the state have refused to comment to Local 6 on unreleased depositions.

Garavaglia also declined comment, though in the deposition, she is not buying the drowning theory.

?We get many cases like that where people are drowned and they always report them because they want them to survive. There?s a chance that you could resuscitate that person,? Garavaglia answered.

Left unsaid: Casey Anthony never reported her daughter missing.

Her mother, Cindy, did call police on July 15, 2008 -- 30 days after she had last seen her daughter and granddaughter alive. But she only did so after locating Casey at a boyfriend?s apartment and discovering Casey had been lying for weeks about her whereabouts and would not reveal where Caylee was.

While finding the manner of death a homicide, Garavaglia said the cause of death is undetermined. There is no evidence of trauma to the body and no traces of chloroform, valium or other drugs found in the remains.

?You just don?t know how it?s a homicide?? Mason asked.

?Correct, based on the circumstances,? Garavaglia responded.

Mason: ?And the circumstances are what you have been told by the detective or other law enforcement people??

Garavaglia: ?No. The circumstances are that a child, an ? almost 3-year-old child is found in a plastic bag, in a laundry bag, dumped in a field to rot with duct tape in the vicinity of the lower mandible,? or jaw.

A bit later, Mason asked: ?Do you agree with the statement that medical examiners are not supposed to be emotionally involved in cases at all??

?I suppose,? Garavaglia said. ?I would think that would be a good idea.?

Then assistant state attorney Jeff Ashton took his turn with the medical examiner -- and he?s all about the duct tape.

Local 6 has learned the placement of the duct tape on Caylee?s skull is going to be a crucial issue in the trial. In fact, the state has commissioned a computer rendering of the skull with the tape superimposed on it and on Caylee's hair. (The state has refused to release it to Local 6 because it contains images of the body and hair, making it exempt from public release under the court?s order.)

But, from Ashton?s questions, one can infer why the placement of the tape could be crucial to proving murder.

First, Ashton reminded Garavaglia that University of Central Florida anthropologist Dr. John Schultz had determined the duct tape was ?covering the mouth and nasal aperture areas.? The latter is the opening in the front of a skull, where the nose would be.

Then, he asked: ?What would have been the effect on Caylee Anthony if the tape had been covering the mouth and nose when she was alive??

Garavaglia: ?I guess it could have suffocated her.?

Ashton: ?If it was not removed, would you expect it to have suffocated her??

Garavaglia: ?Yes, if no air could be passed through any creases.?

Ashton: ?Okay. Is it in your opinion a possible cause of death??

Garavaglia: ?Certainly it could be possible.?

But, unlike the UCF anthropologist she hired, Garavaglia said she ?can?t say for sure whether (the duct tape) was over the nose or just over the mouth.?

Ashton persisted: ?There?s no evidence to suggest any other cause of death other than the tape. Would that be a fair statement??

?Right,? said the medical examiner. ?I believe the tape indicated that there is foul play. I cannot say for certain whether the tape caused a suffocation.?

Then Cheney Mason took over and turned Ashton?s question on its head: ?Is there any evidence that tells you that this child did not drown??

?Again, based on 20 years of being a medical examiner, based on seeing many, many drownings, it?s the circumstances of death that are most disturbing in this case,? Garavaglia said. ?I have never seen a drowning, nor do I see reason why a drowning (victim) would have duct tape on the lower half of the face. I would say that is evidence itself that there?s no indication that this child would drown and there?s no reason why a child that?s drowned is put in a plastic bag and dumped on the side of the road.?