Casey Anthony Defense: No Dirt, No Drugs, No Murder

Despite only having a shortened day of testimony to work with, Casey Anthony's defense team managed to call half a dozen forensic experts to the witness stand today. The expert testimony is part of the defense team's ongoing attempt to dispute forensic evidence admitted by the prosecution -- evidence they claim proves Anthony murdered her two-year-old daughter, Caylee.

Maureen Bottrell was the first person the defense called to testify during day 25 of the trial. Anthony is accused of multiple charges, including capital murder, aggravated child abuse, aggravated manslaughter of a child and misleading law enforcement for the death of her daughter.

The prosecution is seeking the death penalty.

Bottrell, a forensic examiner and geologist from the FBI , testified that she analyzed nearly two dozen pairs of shoes taken from the Anthony home in 2009. Of them, three pairs were found to contain enough soil deposits for comparison to soil samples that were taken from the crime scene on Suburban Drive in Orlando where Caylee's skeletal remains were found.

According to Bottrell, the soil on the shoes did not match the soil samples from the crime scene.

However, during cross-examination, the expert acknowledged that while the soils did not match, she could not rule out the possibility that the shoes had been at the crime scene and then contaminated with soil from other locations.

FBI forensic toxicologist Madeline Montgomery was the second witness to take the stand today. Montgomery testified that she had examined a hair found with Caylee's remains using a liquid chromatograph mass spectrometer and did not find any trace of drugs -- including those containing sedatives or a knock-out effect.

Montgomery's testimony was only a brief win for the defense. On cross-examination, she acknowledged she could not test for chloroform -- a chemical substance that prosecutors allege their experts found traces of in Anthony's Pontiac Sunfire.

Montgomery also conceded that hair is not the best source for showing drug exposure.

"Even if it had been positive, I wouldn't have been able to say when or how often the person was exposed," she said.

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From soil and hair, testimony shifted to forensic chemistry when Dr. Michael Sigman, a professor at the University of Central Florida, was called to the stand.

Sigman said he conducted testing on samples of air from the trunk of Casey's Sunfire, which he found to contain the presence of gasoline, something one would expect to find in a trunk. Sigman said subsequent testing resulted in the discovery of traces of chloroform and other chemicals, which he said are not necessarily connected to human decomposition and are also found in onions, cabbages and Clorox.

"We simply know they're there. We don't know the source," he testified.

Because the amounts were so low, Sigman said he "could not conclusively determine ... that there had been human remains in the trunk of the car."

The defense briefly called Susan Mears, a crime scene investigator with the Orange County Sheriff's Office, to the stand. Mears was asked to identify two items -- a plastic shopping bag and a Gatorade bottle -- that were found at the crime scene.

After Mears stepped down, Michael Rickenbach, a FBI forensic chemist examiner, was called to the stand for a second time.

Rickenbach testified that he was asked to test the Gatorade bottle, a car seat and steering wheel cover from Anthony's Sunfire, and one of Caylee's dolls for the presence of chloroform. He said each of the tests were negative. In regard to the Gatorade bottle, which was discovered with a syringe inside it, he said both items contained testosterone compounds.

The last witness called was Karen Lowe, an FBI forensic expert who specializes in microscopic hair examinations. Lowe previously testified for the prosecution that a hair found in Anthony's car showed signs of decomposition.

On the stand today, Lowe testified that only one hair, of the hundreds she had examined from the vehicle, showed signs of decomposition.

The forensic expert also testified that duct tape fabric found at the crime scene was the same brand as duct tape taken from the Anthony family home, but said testing on the two indicates they were probably not from the same roll.

Lowe"s brief testimony wrapped up the half day, with Judge Belvin Perry dismissing the jurors. He said he had to attend a previously scheduled budget meeting. Testimony in the case is set to resume tomorrow at 9 a.m.

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