ORLANDO, Fla (Reuters) – A research chemist testified on Wednesday that he found evidence of gasoline in air samples from Casey Anthony's car trunk but nothing to indicate that a dead body had been stored there.
"Based on our data, I cannot say there were human remains in that trunk," said Michael Sigman, a chemistry professor at the University of Central Florida.
Casey, 25, is standing trial in Florida for a first-degree murder charge, accused by prosecutors of using duct tape to suffocate her 2-year-old daughter Caylee on June 16, 2008, and then storing the child's body in the trunk of her car. Prosecutors are seeking the death penalty.
Defense attorneys maintain Caylee drowned in the family's backyard pool. Her skeletal remains were found in woods near the Anthony family's home in the Orlando area on December 11, 2008, following a nationwide search.
The trial is in its fifth week, and Wednesday featured a parade of witnesses called by the defense to poke holes in the state's case. The witnesses, mostly from FBI labs, described tests that found no sleep-aid drugs in Caylee's hair, no connection between the crime scene and Casey's shoes and no chloroform on samples of items from inside Casey's car.
Sigman said he first collected two samples of air from the car trunk on July 21, 2008, at the Orange County Sheriff's garage.
By then, Caylee had been reported missing by her grandmother. Prosecutor Jeff Ashton pointed out that the air was sampled four days after the trunk liner and spare tire cover had been removed from the trunk for testing.
Sigman, a former colleague of prosecution witness Arpad Vass at the Oak Ridge National Laboratory, was recommended by Vass to do the collecting.
He left the bags of air with the Sheriff's Office -- one for delivery to Vass, the other one to be brought to Sigman at the National Center for Forensic Science lab, where he is the assistant director for physical evidence.
Sigman ultimately tested three separate collections of air from the trunk. The first, taken by extracting air in a syringe, showed weak organic compounds comparable to gasoline, he said. He then collected samples from the trunk using more sensitive methods.
Those test results were similar to the first, but more concentrated.
"The primary substance identified in all tests was gasoline," Sigman said.
Also present in the air collected by the more sensitive methods were chloroform and other chemicals that have been reported to be an indication of body decomposition, but they were very low responses, Sigman said.
Vass's lab later reported a higher result for chloroform, which Vass said is released by decaying bodies. Vass has testified that the air sample he tested had the strong smell of human decomposition.
Sigman said he also noticed a strong scent when he collected air from the trunk, but gave no indication on Wednesday of what he thought the smell might be.
Maureen Bottrell, an FBI geologist, tested 22 pairs of shoes from the Anthony home, a bag that held the shoes, a shovel, debris from the trunk of Casey's car, and dirt samples from the scene where Caylee's body was discovered.
She said the tests did not connect any of the items to the crime scene.
FBI forensic toxicologist Madeline Montgomery tested the hair found with Caylee's remains and said she found no evidence of drugs such as Xanax, Valium or eight others that are used as sleep aids or tranquilizers.
Michael Rickenbach, an FBI forensic chemist who tested samples from Caylee's car seat, Casey's steering wheel cover and a doll from the car, said the tests identified no chloroform.
Court proceedings ended early because Judge Belvin Perry had a prior commitment. The trial is expected to resume Thursday morning and will be in session all day on Saturday to make up for the time missed Wednesday.
(Editing by Colleen Jenkins and Greg McCune)
