It’s not as if the trial of Casey Anthony for the murder of her 2-year-old daughter, Caylee, isn’t sensational enough, but it will now go down in history as the trial where a piece of forensic evidence was introduced for the first time.  Scent.

Can you smell that smell?  According to the prosecution, they’ve bottled up (canned actually) the smell of decomposing human flesh from the trunk of Anthony’s car, and have offered Arpad Vass from the Oak Ridge National Lab as an expert to testify that it is, indeed, the smell of death.  From the Orlando Sentinel :

[Assistant State Attorney Jeff] Ashton questioned an expert witness in forensic anthropology and introduced the novel science of human-decomposition odor analysis. It was another first for an American courtroom, at least within this specific area of research.

It remains to be seen whether associating specific chemical compounds with dead bodies will emerge as an effective tool in the criminal courts. And it is uncertain how the jurors in this case will value this evidence.

It will certainly be effective to the extent that a witness admitted as an expert says it scientifically proves a point, since that’s the whole purpose of expert testimony, to provide an opinion beyond that which a jury is capable of reaching on its own.

In fairness, it’s really not just about the odor.

Toward that end, prosecutors are introducing testimony by researcher Arpad Vass of Oak Ridge National Laboratory, the story says. Vass took an air sample from the car’s carpet and injected it into a gas chromatography/mass spectrometric to identify substances it contained. Then he compared them to chemicals identified in his research of decomposing bodies at a facility dubbed the Body Farm.

When witnesses testify about cool scientific stuff like gas chromatography and mass spectrometry, it goes a long way toward adding to the scientific panache of the tests.  Jurors are impressed with the use of such devices.  Who wouldn’t be?  But ultimately, Vass’ testimony was about the smell.

Vass backed up prosecutors’ theory, testifying Monday that he smelled an “overwhelmingly strong” odor of human decomposition in the air sample. He told jurors that his machine found high levels of chemical compounds observed when the body breaks down, such as chloroform, in the sample taken from Anthony’s car.

The issue isn’t really whether this is some completely fabricated science, like duct tape analysis, Identifying chemicals in the atmosphere by their color through gas chromatography has been going on for a long time.  It has not, however, been used in this fashion, or to provide information with this degree of specificity.  Nor has it been put through the wringer on various issues related to trials, it’s collection and storage methodology.  No doubt someone with far more knowledge in the science involved would have more astute observations.

In its infancy, almost every forensic science tool has been shown to be wrong to some extent.  Whether greater testing, knowledge, experimentation will prove that it’s viable or a complete fraud has yet to be seen, but the flaws that exist at its initiation eventually come to light.  Later on, we will all laugh and laugh at how silly and simplistic we were in our consideration of some new forensic science when it first emerged on the scene.  Everyone will laugh except the defendant and her lawyer.  Maybe a juror or two will feel badly about buying into a science yet to be adequately vetted for accuracy and all the collateral issues and problems that no one knew about at the time.

Anthony’s attorney, Jose Baez, noted the importance of acceptance to Vass of his work.

During cross-examination Monday, Baez suggested that Vass stood to make money off of his method if it is adopted by police departments.

“You sir, have a financial interest in your testimony here today, do you not sir?” Baez said Monday.

“Not in my opinion,” Vass answered.

Whether that response will add to his credibility or sound facile and disingenuous has yet to be seen, but other scientists, who have no horse in the race without being forced to rely on such a convenient opinion, recognize that this science isn’t, at least not yet, ready for prime time.

But two defense scientists say Vass’ technique is too premature for use in criminal cases.

“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.”

Despite this, Judge Belvin Perry held that the evidence passed the smell test, and the age of odor science was ushered into the courtroom. 

“His opinions and theories range from the interesting to the bizarre,” Anthony’s attorneys said in court documents. But Circuit Judge Belvin Perry ruled that any decision about the reliability of Vass’ methods should be left to jurors.

An interesting, and dangerous, ruling, given that the qualification of jurors to sit requires no proof of their scientific acumen.  How in the world are they expected to judge and reliability of novel forensic science?  Was this covered in 8th grade science?  Is the world flat if 12 jurors decide so? 

The judge is the gatekeeper of scientific testimony, whether it satisfies the Frye test (to which  Florida adheres so no one will have read needless caselaw like Daubert) by showing “general acceptance” if not scientific reliability.  To shrug and kick it over to the jury to decide is mere abdication of responsibility, the judicial equivalent of a punt.  And so the smell test comes in because a judge failed to do his job.

How long will it be before a panel of distinguished scientists reveal that the courts have once again acted prematurely and improvidently by letting another forensic science skunk into the well?  As anyone who has had the pleasure of sniffing the scent of death will tell you, it’s smells horrible.  But then, so does this new bit of novel forensic evidence.  And yet, it’s now been admitted, almost on a lark, and we’ll spend the next few decades figuring out why it stinks and how we ever let this happen in the first place.