How a can of air could put Casey Anthony on death row

Juries often have lots of evidence to weigh when deciding a verdict -- eyewitness testimony, fingerprints, DNA analysis. But this might be the first time they are judging a can of air.

That's one piece of evidence introduced in the case of Casey Anthony, the Florida mother charged with killing her two-year-old daughter, Caylee, in 2008.

An experimental forensics technique that sniffs out the smell of decomposition was used to identify the source of a stench that witnesses testified came from Anthony's car after Caylee's death.

In order to prove that the odor came from a decomposing body, prosecutors enlisted the help of Oak Ridge National Laboratories senior researcher Arpad Vass, who has worked on the chemical composition of the smell of cadavers.

Using a syringe, they extracted some air from a sealed can that held a piece of the car's upholstery. They ran that air through a gas chromatography/mass spectrometry device, which is used to identify molecules, to see what it contained.

They then compared the results from the analysis with a database of 400 chemical compounds that Vass says are released as the body decomposes. He created the list during a four-year experiment, in which he buried cadavers underground, placed hoods over the burial sites and captured the chemical compounds released by the bodies.

Vass testified Monday that the sample had an "overwhelmingly strong" odor of human decomposition and that his analysis showed high levels of the chemicals released during body decomposition, such as chloroform.

But, as with most new scientific techniques, it's questionable whether this evidence will hold much weight in court.

The Seattle Post-Intelligencer quotes two scientists about the experimental nature of this analysis:

"To allow the presentation in court of the findings ... in this case would lend it an aura of scientific authority not justified by its novel nature," said Barry Logan, an expert in toxicology.

Florida International University analytical chemist Kenneth Furton said no scientifically valid method of identifying human remains based on chemical residue existed.

"Previously touted techniques for locating human remains have not been demonstrated to be reliable," Furton said in court documents. He added that Vass' methods "are still in the experimental stage."

The judge has allowed the evidence, so now it's in the hands of the jury. If this method proves crucial in this case, it could be yet another way in which scientific developments change courtrooms.

Photo: screenshot, CBS News

via Popular Science

This post was originally published on Smartplanet.com