ORLANDO — A chemist who collected and tested air samples from the trunk of Casey Anthony's car testified Wednesday that he couldn't say for sure there was ever a body inside of it, statements that conflict with prosecutors' experts.
Defense witness Michael Sigman pulled the samples from Anthony's trunk six days after she was arrested on murder charges of her 2-year-old daughter, Caylee.
The child's skeletal remains were discovered in a wooded area in December 2008.
He was one of five witnesses to take the stand as the defense continued to attack the prosecution's contentions that the toddler was suffocated by duct tape and then spent at least some time in the trunk.
"I cannot conclusively determine that there were human remains in the trunk," said Sigman, a chemistry professor at the University of Central Florida.
Anthony is charged with first-degree murder in her child's death. She has pleaded not guilty and could get a death sentence if convicted.
The defense says the toddler drowned in her grandparents' swimming pool.
Anthony's defense team also called a geologist, toxicologist and fiber analyst — all from the FBI — as witnesses on Day 25 of the trial, which was only a half-day because of a prior commitment for Judge Belvin Perry.
Sigman's testimony conflicted with research scientist Arpad Vass, a former colleague at Oak Ridge National Laboratory. Vass, a witness for the prosecution, said he determined human decomposition in the trunk based on an unusually high amount of chloroform found on a carpet stain.
Prosecutor Jeff Ashton pointed out during his cross-examination of Sigman that by the time the chemist collected his air samples, the trunk's carpet and spare tire cover had been removed.
"So your samples only tell you what was in the air, it doesn't tell you where (any gasses) came from, correct?" Ashton said.
"Yes," Sigman responded.