That’s how they used to test witches: if they floated it was witchcraft; if they sunk they were innocent.

On Saturday morning superstition was entered into the trial of Casey Anthony as evidence. Her attorney, Jose Baez, tried to explain to Judge Belvin Perry that “hair banding” isn’t science, but failed. Baez apparently isn’t a very experienced trial attorney and was unable to find legal precedents for his objection to the evidence, but he was right in everything he said.

I’m not a lawyer and certainly not a scientist, but I understand how legal  precedents work (or, as is usually the case, do not) and I also understand the scientific method. There’s very little science in most so-called “forensic science.”

What I am is an expert in reading English language texts, which apparently none of the lawyers in the Anthony courtroom are, or they would have understood the following passage in the National Academy of Sciences report titled “Strengthening Forensic Science in the United States”:

“In cases where there seems to be a morphological match [between hairs] (based on microscopic examination) it must be confirmed using mtDNA analysis; microscopic studies alone are of limited probative value. The committee found no scientific support for the use of hair comparisons for individualization in the absence of nuclear DNA. Microscopy and mtDNA analysis can be used in tandem and may add to one another’s value for classifying a common source, but no studies have been performed specifically to quantify the reliability of their joint use.”

Hair Bands (not the accessory)

On Saturday I witnessed one of the least scientific, most superstitious presentations it is possible for a prosecutor to make: the State introduced an FBI hair-and-fiber examiner to confuse the jury with a nine-inch-long hair that may or may not have been the victim’s and may or may not have exhibited a phenomenon known as “hair banding”—and without even  presenting a photograph to show the jury what the hair really looked like.

Hair banding is nothing more than a discoloration of a human hair near the root. It only appears in some hairs, not all. No one knows what the chemical reaction is that causes the discoloration. Hair banding has occasionally been found in hairs taken from a decomposing human body. When a hair from a decomposing body displays this discoloration, it may or may not be the only hair from that body that displays this characteristic. The hair may or may not still be in its follicle when the banding occurs; the hair may or may not have been pulled out of the body when it occurs; the hair may or may not have fallen out of the body when it occurs. Hair banding “usually” occurs 2 to 4 days after death, according to less than 5 research studies—if it occurs at all.

The FBI witness said she had heard of a banded hair being observed 8 hours after death. She did not tell the jury what the longest time after death she had heard about in which hair banding had occurred—so for all we know it could be weeks or months later, nor do we know yet whether Caylee Anthony’s remains included any banded hairs. Or any hairs at all, for that matter.

And, if I’m not mistaken, the FBI expert said that the lone hair in question was the first hair she had ever examined when she did not know what body it had come from. In other words, all the other banded hairs she examined were plucked from or had fallen from a KNOWN DEAD BODY!

Let me be clear about this: the FBI expert had previously expressed an opinion about hair-banding only when she knew for a fact whose body it had come from.

She has only used banded hairs for purposes other than to claim a specific dead body had been in a specific location. (In other words, she had never used hair analysis to identify a dead body.) The Anthony case is the first time she ever did what she did.

In the Anthony case, a hair found in a specific place is suspected of coming from a dead body, but the FBI expert can’t tell which dead body it came from. The prosecution doesn’t know whose dead body it came from. It’s a hair that looks similar to hairs found in Caylee’s hair brush. But the FBI expert has always before studied hairs from known corpses in the custody of the authorities. (In fact, Baez tried to introduce testimony about a case in which another FBI expert mis-identified a banded hair using this same faulty methodology, which resulted in a false conviction, but the judge didn’t seem to understand this, and Baez wasn’t able to make it clear.)

Sidebar: Much as I admire Judge Perry, several times in this trial I have observed him to mistake scientific instrumentation for scientific method. (More about that later.)

There is no scientific data about such discoloration occurring in hairs pulled or fallen from living human bodies. You heard me right: no scientist, forensic or biologist, has ever researched the possibility of living people shedding hairs which subsequently display hair banding. None. No “peer-reviewed journal articles.” Given the gazillion hairs out there today on Planet Earth, the odds are, folks, that a living person’s hair has at some time discolored once it left its nurturing, little follicle.

The fact is, forensic science does not know whether hair banding is a phenomenon exclusive to human decomposition or not.  They cannot say whether hair banding occurs in all mammals. And until they figure out what the chemical process is that causes hair banding, they cannot even say whether it is a real process or just a random event—and random events do occur in nature.

But don’t confuse the FBI alchemists with logic.

The discoloration of that nine-inch hair, which forensic “scientists” call “hair banding,” is actually the least of the logical fallacies I heard presented by the FBI expert and the prosecutors during Saturday morning’s testimony, but in this blog I want to focus on it, because Baez raised issues taken from the above National Academy of Sciences report on the failings of forensic science and its misuse in court. This report should be studied by every criminal court judge and every trial lawyer.

In 2009 the National Academy of Sciences (which is something like a standards board for the scientific method) issued a report warning the justice system in this country of abuses of forensic science as evidence in trials. The report stressed the value of DNA evidence, when properly used, and the fallaciousness of many other forms of forensic evidence, especially “hair and fiber” evidence, for which there are no analysis tools. (Using a microscope to peer at a hair is not an analysis tool; it is a tool of art and craft; its value is entirely dependent on the skill of the observer. Real scientific instrumentation does the job itself and prints out a report—I’m also an expert on this because I was once an editor for The Astrophysical Journal.)

In other words, hairs and fibers can be chemically analyzed, but all that such chemical analyses will tell an investigator is that a hair is a human hair and a fiber is a fiber of one type or another. No scientific analysis can tell a jury that a given hair came from a given person unless the hair root contains nuclear DNA. Mitochondrial DNA (mtDNA) can be used to tell whether the hair came from a person with a specific matrilineal ancestry. In a case such as the Anthony case, a hair root might be able tell whether or not the hair came from Caylee, Casey, or Cindy, or even Cindy’s mother, but not which one of them it came from. Logically, though, if the hair had been colored or chemically treated, that would rule out Caylee, but not the adult women.

But the nine-inch hair did not have sufficient root present to contain any DNA—therefore, there is no scientific way to prove it came from the victim in this case.

It ought not to have been used as evidence before the jury, if you understand the NAS report.

By now it should be obvious that I don’t believe there’s sufficient evidence to convict Casey Anthony of murder. However, from listening to the jury voir dire in this case I also don’t think there’s anyone on the jury who will understand how bogus this hair banding evidence is. Nurses are not scientists, although they probably think they are. At this point, the defense has to hope that someone on the jury will understand all the other illogical assumptions the prosecution is making about this lone hair among all the other hairs found in the Anthony car and about the car itself. (There’s at least another blog to be written about those absurdities, too.)

Reread the above statement taken from page 161 of the NAS report: There is no scientific literature (peer- reviewed journal articles) that says it is possible to identify a person using a lone hair without so much as mtDNA. Let me make this even clearer: no scientist would bother to use a microscope to compare hairs if he or she did not also have DNA samples for confirmation.

Yet the Anthony jury heard testimony that such a hair was consistent with Caylee’s hair and could not be ruled out as possibly being Caylee’s hair—that’s identification, folks.

If were Jose Baez, the first witness I would call in the defense case would be a member of the National Academy of Sciences whose expertise is in the scientific method.