The judge in the Casey Anthony murder trial is expected to decide whether to let jurors smell air samples from a car trunk that witnesses have said reeked of human decomposition.
Use of the air samples would be controversial and a groundbreaking legal tactic. It could also pose a danger to the prosecution's effort to convict Casey Anthony for the death of her 2-year-old daughter, Caylee in 2008.
One expert described the use of the untested method as an "O.J. Simpson moment," referring to the use of a glove that backfired on prosecutors when it didn't fit Simpson's hand.
"It's a new forensic technique that has not been tested by the courts and so whenever that happens, the court has the responsibility to make sure that the science behind it is solid," said Michael Seigel, a University of Florida Levin School of Law Professor.
The prosecution has not yet asked to open the canisters containing the air samples, but they did put Dr. Arpad Vass on the stand today. Vass is the man behind the groundbreaking science that analyzes the air samples. He spent the morning explaining his expertise in research about the smell of human decomposition. Vass works at the Oak Ridge National Laboratory in Tennessee where he analyzes the odor of death by working with cadavers at a "body farm."
He is essentially working towards finding a signature for human decomposition that will lead to the creation of an electronic detector that does the work of a cadaver dog. His research is already being used by the FBI to create a database of the chemical compounds found in human decomposition.
Vass said that the air samples taken from the trunk of Casey Anthony's car had an abundance of chloroform, a sign of human decomposition and a chemical that also can be used to commit murder.
"I essentially jumped back a foot or two…I was shocked that that little itty bitty can could have that much odor associated with it…I would recognize it as human decomposition," Vass told jurors.
The way an air sample is taken is first through a stainless steel tube called a triple sorbent trap. The triple sorbent trap is full of three types of activated carbon. The tube is placed near where the odor is emanating, whether it be a body bag or in this case, a carpet sample from the spare tire cover of Anthony's car. An air pump is used to draw air into the trap. The trap is then sealed. The stainless steel tube is then heated up to concentrate the sample. From there, the sample is injected into a gas chromatograph/mass spectrometer test which finds the chemical compounds present in the sample.
Vass said that chloroform is normally found in trace amounts, in parts per trillion. The trunk sample showed chloroform in the parts per million range, significantly higher than the average.
"We were shocked. We had never seen chloroform in that level in environmental surroundings before…at least I never have," Vass said.
Until today's testimony, the prosecution has mainly relied on surveillance videos, the testimony of friends and family and jailhouse conversations to establish Anthony as a liar who was not looking for her daughter when only she knew that Caylee was missing.
Now the prosecution hopes Vass's testimony will provide the much needed physical evidence linking Anthony to the murder of Caylee.
Anthony's defense team claims Caylee accidentally drowned on June 16, 2008. Caylee wasn't reported missing until July 15, 2008. Her remains were found in December of that year.
Vass's emerging research has never been used in a criminal trial before. The defense fears that the prosecution will be allowed to unscrew the lid off the canisters containing the smell of death and allow jurors to take a sniff.
"The prosecution contends that there's an odor to the naked nose and they want the jurors to smell it. Typically, we do allow jurors to experience the tangible evidence...if it's a photo, they can see it. If it's a gun...they get to look at it and if they really want to, as long as it's not loaded, they probably get to touch it," said Seigel.
Seigel said the testimony of Vass is damning enough for the 25-year-old Anthony. She could face the death penalty if convicted.
"If the odor is there, it's extremely damaging because it's obviously a hard fought point and the fact that there would be the evidence of the decomposition in her automobile is extremely significant and corroborates a lot of evidence...it would be a very important nail in the coffin," said Seigel.
But it could also be a risky move the prosecution if Judge Belvin Perry allows the cans to be opened.
"This is the kind of moment in the case that can make it or break it," Seigel said. "If the judge allows them to smell it and they don't smell anything, to me, that's like the O.J. Simpson glove incident where the glove didn't fit."
Simpson's not guilty verdict in the murder of his ex-wife was attributed largely to the prosecution's claim that a glove involved in the murder belonged to Simpson, but when he was told to put on the glove in court it did not fit.
Use of the novel approach could also turn out to be crucial in a potential appeal of a guilty verdict.
"Whether or not this evidence should have been admitted in the first place because of it being novel and untested. That gives them a juicy appellate issue," Seigel said.