by Jeff Ashton
We had six samples from six cases, along with a sample from the defendant. The lab in New York was able to get results in two of the six, and matched them to the defendant. We added the names of the lab personnel who had done the testing to the witness list. Nobody else in the United States had ever used this kind of evidence in a case, but even so, I don’t think we fully realized how earth-shattering this DNA evidence would be for prosecutors and defense attorneys alike. The bottom line was that we thought it was cool, and we were excited to be the ones giving it a shot.
We decided to get an expert not affiliated with the lab to testify, choosing David Housman, a molecular biologist and a professor at MIT, to explain the science behind what we’d done. Fortunately for us, the judge who happened to be assigned to the Andrews case, Judge Rom Powell, had experience in judging trials that hinged upon cutting-edge forensic evidence. He had been the first to rule on a case that was used a new science called voice print identification. We had a Frye hearing, which is a specialized process to determine whether a new scientific tool is based on generally accepted, established scientific principles.
“Frye hearing” comes from a 1923 case in which a fellow by the name of James Alphonso Frye was being tried for a murder in Washington, D.C. His lawyer wanted to present to the jury evidence from an expert who claimed that the truth could be determined by looking at changes in the blood pressure of an individual during an interview, an early version of the lie detector. The trial judge ruled that the evidence was not admissible, and the appeals court agreed. Those decisions contained a single sentence that to this day determines the admissibility of scientific evidence in Florida and most jurisdictions in the United States: “the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.”
The precise meaning of that sentence has been the subject of fierce debate over the last ninety years, and you could write an extremely boring book exploring all of its nuances. Simply put, it means this: the court will admit new science only if it has a firm foundation in established science.
In the Andrews case, the Frye hearing to determine the admissibility of our DNA evidence was ruled in our favor. After we successfully argued the Frye hearing, Tim Berry and I tried the case; I presented almost all the evidence and made the closing arguments. The jury found Andrews guilty of rape and other charges.
The process used for that DNA analysis was very primitive, and about four or five years later a much better process was developed that could get far more accurate results using much smaller amounts of DNA. The probability numbers back then for whether the DNA actually came from a particular individual were one in a hundred thousand. With today’s technology, the results are closer to one in a quadrillion, which would include just about every human being who had ever lived. In 2004, Andrews asked to be retested, claiming that the DNA results in 1988 were inconclusive. The state complied with his request, and a subsequent DNA test was still a match. Tommy Lee Andrew is serving a combined sentence of sixty-six years for the two rapes.
IT’S BEEN ACCEPTED FOR A long time that all scientific advancement comes from those with vision standing on the shoulders of those who came before them. It’s simply a matter of taking something that already exists and using it in a new way. The full-on nerd part of my personality finds this fascinating.
The more Dr. Vass and I shared information about our backgrounds and interests, the more I was able to convince him that this was a case that demanded his testimony as an expert witness. We talked about every aspect of his work—what inspired him, what techniques he borrowed from other disciplines, and how he came to his conclusions. We discussed the process of publication in scientific journals and the responses of his colleagues in the field. In the short time that I’d been researching odor for this case, one of the difficulties I’d found was that there were very few people who worked in this field. However, I was lucky to have one of the few pioneers on my side.
Reassuring as that was, there were still drawbacks. Dr. Vass’s field of study, odor mortis, or the smell of death, was more complex than DNA, and I knew from that first phone call that the forensics would be difficult. The main challenges in trying to collect a forensic sample of an odor are threefold. First, how do you capture the odor in a pristine form? The moment you expose a sample of air to room air, the concentration of the compounds that make up the odor are diluted. Second, further complicating the process is that once the ambient air mixes with the odor, how do you know that the compounds you find come from the sample and not the ambient air? Third, you need to establish that the compounds you find are being released from something that is still there and not an odor left behind by something that has been removed.
To help answer some of these questions about sample odor collection from the Pontiac, the crime scene supervisor for the Orange County Sheriff’s Office, Mike Vincent, went to Dr. Michael Sigman, a former colleague of Dr. Vass at Oak Ridge. Sigman was with the National Center for Forensic Science at the University of Central Florida. The first attempt to collect the odor sounded simple enough: open the trunk just enough to insert a small hose and, using a large syringe, pull out a volume of air and then expel it into a bag. But that method failed to collect a sufficient sample of air to get any reliable result.
Next, Dr. Sigman used the best technology available to him, placing small synthetic fibers, known by the acronym SPMI, into the trunk for a period of time. The fibers act as adhesives to compounds in the air, capturing those compounds immediately surrounding the fibers. The difficulty with this method is that it can sample only the very small volume of air that happens to pass over the fibers. Since the air in the trunk couldn’t circulate, the sampling of the air was just too limited to determine the existence of compounds in very small quantities. The test did nothing to tell us what the odor was emanating from.
Finally, Dr. Vass suggested that we cut a small sample from the stained carpet itself, seal it in a small metal can, and mail it to the Oak Ridge Lab to be tested by him. He took the carpet sample and placed it in a special bag made of a plastic designed not to react with the substances placed in it. Vass then heated the carpet to the approximate temperature that would have existed in the trunk, removed a sample of the air, and cooled it to concentrate the sample. After the cooling was complete, he ran it through a gas chromatograph/mass spectrometer, a device commonly used by scientists to break a substance into its underlying compounds. The results of all this demonstrated that the odor coming off that stain was consistent with what his research had detected coming off a decomposing human body. Equally important was that it did not match the research on decomposing animal remains.
Another smell that needed analysis was that of pizza. Ever since Casey’s arrest, there had been comments by the defense and the Anthonys in the media attributing the smell in the trunk to that of a rotting pizza. An empty pizza box had been found in the garbage bag that had been removed from the trunk while the car was at the tow yard, although there were only crumbs of pizza left. Vass wanted to know if that was possible, so he took a pizza out of his freezer and let it rot in his backyard for a week, then tested the odor. The two smells didn’t match.
Vass offered to test another possibility that had received speculation in the media: that the odor was from a road-killed squirrel stuck to the car’s undercarriage. This is what Casey had alleged in a couple of her texts to Amy Huizenger during the thirty-one days that Caylee was missing. I told him that testing a squirrel would be great, but I didn’t want him running out and killing any innocent squirrels. He laughed and expressed confidence that in rural Tennessee he’d be able to find some roadkill to test, which he did. The dead squirrel didn’t match the odor from the car either.
In addition to the pure science he had applied to the problem, he had another tool at his disposal: his nose. Having studied odors as much as he had, he was uniquely qualified to
identify them and the differences between them. The first time he opened the paint can containing the carpet sample, he told me he jumped back two feet, the smell was so unmistakable and strong. He was certain it was the smell of death.
His testing of the carpet fibers revealed fatty acids and inorganic elements in concentrations consistent with human decomposition. In addition, he tested a suspicious greasy substance on a paper towel that had also been in the garbage bag from the trunk. He found that the substance on the paper towel was chemically identical to another by-product of decomposition called adipocere, or “grave wax.” None of these findings alone was an irrefutable sign of the presence of a dead body, but the combination of them all was starting to paint a clearer forensic picture.
Of Vass’s findings, there was one more piece of particular interest that was also perhaps the most disturbing. The results of his tests identified a high level of chloroform in the specimen of carpet from the Pontiac’s trunk. The levels were so high, in fact, that chloroform was the most prevalent compound discovered. Dr. Vass explained to me: while chloroform might be produced by human decomposition, it would be in extremely small amounts. The amounts revealed in his test were thousands of time greater than he had ever seen from a decomposing body. In his opinion, the chloroform had another source, although he could not establish it. This discovery of chloroform in the trunk was later confirmed in testing performed by the FBI.
The presence of chloroform in the trunk sample was a surprise to all of us. Chloroform had been known to be used as an anesthetizer to knock victims out, and it wasn’t something you could get at the local drugstore. Since it wasn’t a commonly abused product, Detective Melich thought it might be worth a shot to check the Anthonys’ computers to see if anyone had tried to buy it online.
Detective Sandra Cawn, an experienced computer forensics investigator with the Orange County Sheriff’s Office, had already been mining the Anthonys’ computers for any leads that might help us learn the whereabouts of Zanny. Melich asked if she could also check for searches involving the word “chloroform.” Detective Cawn first searched the hard drive of the laptop that Casey had been using at Tony’s and found nothing. She then turned her attention to the desktop computer used at the Anthony home.
Her initial inspection of the active files came up empty. She then looked at the unallocated space of the hard drive. As it was explained to us, when you permanently delete something from your computer, that digital information gets transferred to another space on the hard drive, where it can then be overwritten with new information. This computer version of limbo is called “unallocated space.” Even though we think the file is erased from our computer, in fact it may still be there. Over time, all or portions of the information will be truly erased, as new information takes its place. Until that happens, though, a computer forensics investigator armed with the right software can mine that data.
When Detective Cawn examined this part of the Anthony family’s home computer, she found repeated references to the word “chloroform,” but that was as far as her software and her experience could take her. She turned to her boss, mentor, and teacher, Sergeant Kevin Stenger, and using more sophisticated software—even some that was still in development—Stenger was able to determine that on two afternoons in March someone had performed searches for information about chloroform. In one of the searches, someone had actually typed in the query “how to make chloroform.”
Given the dates listed on the chloroform searches, Detective Melich wanted to be sure who had access to the computer those afternoons. He thought Cindy and George had probably been out of the house, and subpoenaed their work records to see if they were at their places of employment at the time the searches on chloroform were being done. Cindy’s work records showed she was working both those days at those times. George’s work records showed he was not actively employed that month, but worked a ten-hour day on one of the afternoons the searches had been done.
Finding chloroform in the trunk and in the search history of the computer added a new layer of suspicion to the case. These, along with the results from Dr. Vass’s odor tests, point toward foul play of some kind.
Useful as all this was, it wouldn’t do us much good if we couldn’t convince the court to accept the science behind it. In other words, the time would come when we would have to establish the admissibility of Dr. Vass’s work and the opinions derived from it. When the time came for the Frye hearing, it would be my job to convince the court that this new science of Dr. Vass’s had a firm foundation in established science. After all, that was why I’d been brought on the case in the first place.
INTRIGUING AS THE POSSIBILITIES WERE with the odor, they were only one part of the forensic evidence in our possession. My second forensic project was the hair collected from the trunk of the Pontiac. We wanted to establish that it was Caylee’s hair, but more specifically, we wanted to determine whether the hair had come from someone living or dead.
The person I called was Karen Lowe, a senior analyst in the Trace Analysis Unit of the FBI Crime Laboratory Division in Quantico, Virginia. Lowe was a scientist with eleven years’ experience at the lab. I read her report on the examination of the hair found in the trunk, and our conversation about her findings was professional and to the point, as you would expect. In her examination of the hairs, she discovered that one of them, a nine-inch light brown hair, had an unusual dark band at a particular point near the root. She explained to me that, while science has yet to understand precisely why this banding occurs, it has only been found in hairs taken from decomposing bodies. The banding was first documented in the scientific literature in the late 1980s and has been documented in numerous studies since. She noted that she had personally seen it hundreds of times in case work while examining hair known to have been taken from dead bodies, but that this was the first time she had seen it in a scene sample where the body had not been found. In the conservative fashion typical of FBI reports, she could only describe the banding as “apparent decomposition,” but with the explanations she was able to give me, I felt we had a bombshell.
The next issue was proving that it was Caylee’s hair. Lowe had examined the hair under a microscope and compared it with hair taken from a brush that the Anthonys said was Caylee’s. Hair comparisons aren’t like fingerprints; no expert can ever say with certainty that two hairs have come from the same person. By looking at the microscopic features of a hair, however, a scientist can eliminate some possibilities. Lowe explained that her comparison revealed that the hair with the banding was similar in length, color, and all other microscopic features to the hair taken from Caylee’s brush. She also compared it to samples of Casey’s, and she was able to say with confidence that the hair could not have been Casey’s, because her hair was colored with dye and too short. We knew that Cindy’s hair was dyed, usually blond, and kept short, and Lee’s hair was too short as well. In order to be as certain as possible, the hairs were passed on to the DNA section of the lab.
Now, because DNA can only be extracted from a living cell, ordinary DNA testing doesn’t work on a hair. Because the only living part of a hair is the root, decomposition makes the chances of successful regular DNA testing of hair slim to none. However, there is another kind of DNA test that can work on hair, a test that examines the DNA found in the hair’s mitochondria. The DNA in the mitochondria is much heartier than ordinary DNA, and therefore it exists even in the dead cells of hair. The downside of mitochondrial DNA (mtDNA) is that it is passed on only from mother to child; there is no contribution from the father. Your mtDNA is identical to that of all your brothers and sisters, your mother, all of her siblings, your grandmother, and all of her siblings. In other words, if there is an unbroken maternal connection, then the mtDNA is a match.
The results of the mitochondrial DNA tests were a match. This match, combined with the fact that we’d already microscopically eliminated Casey, Cindy, and Lee by length and color, made me pret
ty confident that the hair with the “death band,” as the media would come to call it, was Caylee’s. With Dr. Vass’s findings and the other evidence of the smell, it seemed a sad but inescapable conclusion that Caylee was dead.
Still, the challenges to all these forensics would be many. The Frye hearings would be a monster. No doubt the defense would be digging up opposing experts, who were often attracted to big cases for the notoriety it would bring them. There would be requests for examinations of the same samples, logistics surrounding transporting those samples—not to mention depositions, travel, and more time for me spent away from home. And then, assuming we made it past the Frye hearings, there was the difficulty of presenting this cutting-edge science in such a way that the jury might actually understand it.
It was going to be a busy couple of years.
CHAPTER TEN
TRACKING DOWN LEADS
The forensics may have been coming together, but we still couldn’t treat this solely as a homicide. Throughout August and into the early fall, the police continued to chase after leads connected to both a possible kidnapping and a possible murder, while interviewing everyone with a link to Casey and of course trying, without success, to get more information from Casey herself.
At the Anthony home, the public was going nuts, with news trucks on their street night and day. Any time Cindy or George left the house, protesters would scream hateful and often ignorant things at them. One woman in front of their house had a child holding up a sign reading WOULD YOU KILL ME? I was disgusted by some of the things they were doing. I’d been around big trials before, but this was something else altogether.