Expert Says “No Other Plausible Explanation” for Chemicals in Trunk Besides Human Decomposition

Dr. Arpad Vass concluded his testimony in Casey Anthony's murder trial on Monday afternoon, defending his conclusions under cross examination as attorney Jose Baez tried to paint him as outside the scientific mainstream and suggested that his ideas are unsupported by anyone else in his field.

Vass—-who testified in the morning that air samples he tested from the trunk of Anthony's car contained chemical compounds consistent with human decomposition—-stated more definitively at the conclusion of his direct examination by prosecutor Jeff Ashton that he "can find no other plausible explanation" besides human decomposition to explain all of the results his analysis found. He said that tests performed on the air, the carpet and paper towels from the trash confirmed that the carpet was the point source of the odor.

The cross examination by Baez frequently focused on Vass' background, his alleged financial interest in successful testing results and the fact that no other scientist in the US has replicated his findings. Baez repeatedly questioned Vass' qualifications to testify about chemical compounds without a degree in chemistry or biochemistry. Vass refers to himself as a "research scientist" and has a degree in biology with a PhD in anthropology.

Baez also suggested that Vass stands to profit off of an invention called the Labrador that would use his gas chromatograph technology to assist police departments with searching for dead bodies. Vass acknowledged that a patent disclosure form lists him as an inventor, but he said the decision to file for the patent was the laboratory’s, not his. He also seemed unfamiliar with the licensing fees and royalties he might be entitled to, noting on redirect that he actually had to go ask others about it after the issue was raised in his deposition last year because financial considerations never interested him.

Getting to the substance of Vass’ findings, Baez pointed out differences between a preliminary report completed in August 2008 and a second report completed several months later. The second report indicated slightly fewer chemical compounds consistent with decomposition than the first, and Vass explained that was partly due to removing duplications and the fact that some overlapped with the properties of gasoline. He said they were ultimately “very, very conservative” in including only five significant chemicals in the final report.

Vass acknowledged that he did not know any details about the history of Anthony’s Pontiac Sunfire prior to July 2008 or any information about the history of two Pontiacs taken from a junkyard that were used for control samples in his tests. He also stated that they did find trace amounts of chloroform in the trunk of one of those vehicles.

Baez then asked Vass about paper towels found in the trash that had traces of fatty acids associated with decomposition. He suggested that the acids could have come from a hamburger or a chicken, but Vass noted several conditions that would be necessary for that to be true, for example several pounds of raw hamburger meat wrapped in a bag in a specific climate. He said somebody eating a hamburger and wiping their face with a paper towel would not produce the results he observed.

Outside the jury’s presence, Baez questioned Vass about a comment he reportedly made in May 2008 that this science was “in its infancy stages.” Vass was quoted as saying that in an article about his failed efforts to locate bodies on a ranch once used by the Manson family. Judge Belvin Perry ruled that since that search was done under completely different conditions, it had no bearing on this case.

In front of the jury, Baez asked Vass about another quote, this one from a Knoxville newspaper in December 2008, where he compared the smell of human decomposition to a rotten potato, calling the two “amazingly similar.” Vass acknowledged that he may have said that, but he has also studied the chemical composition of a potato and it is completely different.

Vass testified that, while others have done studies on pieces of tissue, he is aware of only one other scientist in the world who has produced findings similar to his, a doctor in Greece who looked at bodies at a single point in time, whereas Vass’ study was conducted over several years. He did not recall exactly, but he stated there was a lot of overlap between the 470 chemical compounds he identified and the approximately 80 that the Greek study found.

When asked about using a stained blanket from a case in Montana where a child’s body was wrapped up in the trunk of a car for control samples, Vass said it was fortunate that they do not find many dead children in cars so there were not many options to compare the samples from Casey Anthony’s trunk against.

Prosecutors are expected to call their next witness at 9 am on Tuesday.