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By: Douglas Page  
Issue: June/July 2007

How a small town murder investigation stimulated science on the forensic frontier.

Figure 1: Det. Paul Dostie at the site of the shallow grave where the victim was found.

At first, no one knew how she died or when she was disposed of in a shallow grave on a ridge above Mammoth Lakes, California. Her remains were found in 2003. It has taken four years to figure out who she is.

“In homicide investigation, on Day One you want to know who the victim is, and if it’s a woman who the husband or boyfriend is,” Detective Paul Dostie said. Dostie, a propensive 20-year veteran of the Mammoth Lakes Police Department (MLPD), caught the case. Mammoth Lakes, a ski resort community 8,000 feet up the eastern slopes of the Sierra Nevada, doesn’t get many murders. This was his third homicide.

“The vast majority of the time when women are killed it’s by a significant other. Women don’t get into bar fights and get stabbed,” Dostie said. “Once we have a positive identification we have a place to go.” He meant the suspect. Dostie thinks he knows where he is.

Then, instead of focusing all his attention on learning the victim’s identity, he can get to the fun part.

“That’s the most satisfying thing of all – getting the guy who thinks he got away with it,” Dostie said.

What’s most gratifying so far, though, is the help he’s gotten from the Dream Team of scientists and academics he’s recruited, most of whom have contributed technologies never before used forensically. The search for her identity has led to arcane studies of the victim’s teeth, bones, flesh, and hair to find clues about her diet, the water she drank, where she lived, and when she gave birth.

“This is a world that law enforcement is unaware of and with the exception of ancestral DNA none of this has been used in a criminal investigation before,” Dostie said.

Without these technologies Dostie would still be holding a box of unknown bones. Instead, he believes he knows who the victim is. Final mitochondrial DNA confirmation is pending.

One recent Sunday morning, Dostie slipped on a pair of latex gloves, opened an evidence box marked “03-0929 187 PC,” then placed a skull on the table.

“Meet Barbara,” he said.

Dostie believes the remains found scattered on that hillside are Barbara Pacheco Santiago.

MISSING REPORT
No one reported her missing. Only her killer knew where she was until a dog found her skull on a slope 1,000 feet above Mammoth Lakes, in May, 2003.

Later that week pieces of the rest of her were found, in and around a nearby shallow, clandestine grave, at the top of a ridge known as Mammoth Knolls, near the edge of a cliff with a lover’s lane view of the city – an almost affectionate place to leave someone.

The grave, now no more than a small depression in the shade of a red fir surrounded by a low buffer of manzanita shrubs, was empty but for some torn clothing and a few bone fragments. Her Kmart Jaclyn Smith wristwatch was still running.

After a forensic examination at the medical examiner’s office in San Francisco, Dostie was informed the victim was 4-ft, 6-in to 4-ft, 9-in, female, 30-40 years, and had been dead for close to nine months. This meant she had spent the winter in the snow, exposed to mountain climate and carnivores.

The examiner also said she could be Asian. Dostie focused the investigation in that direction.

After a fruitless 15 months looking at Oriental angles, Dostie learned that DNA can be used to determine genetic heritage. Dostie sent a femoral fragment containing bone marrow to DNAPrint Genomics (Sarasota, FL) for the analysis of nucleotide polymorphisms (SNPs). SNPs frequencies have been shown to differ considerably between major geographic populations and when analyzed can be used to make inferences about a person’s bio-geographic ancestry, or BGA. DNAPrint uses a proprietary test called DNAWitness 2.5 to show relative amounts of European, East Asian, Native American, and Sub-Saharan African ancestry.

The results came back in August, 2004. The victim was not Asian, but 100 percent Native American.

The case was redirected. Dostie could now focus the investigation on the Western Hemisphere, and probably North America.

“This not only turned the investigation around, it opened up a new DNA world,” Dostie said. “None of the information DNAPrint provided is available in any government-run crime lab.”

Currently, when DNA is collected at a crime scene and there is no match in the 4.4 million profiles (as of Feb 2007) contained in the FBI’s Combined DNA Index System (CODIS), the case likely goes cold unless there is other evidence.

“Now, from DNA BGA analysis, we can get racial makeup and eye color,” Dostie said. “Before long BGA will also give us hair color.”

Matthew Thomas, DNAPrint’s senior scientist, believes within five years crime scene DNA will yield complete descriptions.

CONFLICTING REPORTS
At the time, however, Dostie had conflicting reports. The medical examiner said she could be Asian. DNAPrint said she was Native American. Now what?

Soon after he got the DNAPrint results, Dostie went online. Since he had a box of old skin and bones he figured he needed a physical anthropologist. He Googled “physical anthropology” and discovered the American Association of Physical Anthropologists. He called the president.

“I started at the top,” Dostie smiled.

The president at the time was Phillip Walker, Ph.D., a well-known anthropology professor at the University of California, Santa Barbara.

Walker, who is an expert on prehistoric Native Americans in California, agreed to lend his expertise, and his extensive academic contacts, for free provided Dostie agree to follow the case to the end. That was easy; the tenacious Dostie is known in the 20-person MLPD as someone who never lets go.

Dostie shrugs when asked why he spent so much time trying to identify a woman from outside his jurisdiction no one missed. “It’s what I do.”

The remains were delivered to Walker’s campus lab. Walker still has everything except the skull. They are stored in a flimsy cardboard shipping box the size of a beer cooler, double wrapped inelegantly in black cinch bags with loose red draw strings, alone on the bottom shelf of a doubledoor storage cabinet in the locked Lab Supply room on the ground floor of the Humanities and Social Sciences building.

The box is surprisingly light, considering it contains the remains of a human female.

Inside the box, enfolded in waxed paper, resting on a bed of bone fragments, is what remains of her torso after spending a winter in the woods – hollow, mutilated, the skin nearly unrecognizable now, gnarled, tough, and twisted, like a dry chamois, braided almost by the alpine beasts that tore at her flesh.

“Based merely on size and hair color I immediately thought this person looked like a Mesoamerican farm worker,” Walker said at his lab one recent afternoon.

One of the first things Walker did was perform a proper autopsy; something he suspects was neglected when the remains passed through the San Francisco medical examiner’s office 15 months earlier.

“At first I just wanted to figure out how old she was and get an idea of her ancestry,” he said.

As Walker and two students did their examination on the mummified abdominal skin, they found a couple of narrow, one-inch slits in the chest, one just below what Walker believes is a nipple.

“That’s a knife wound, not an animal bite,” Walker said, pointing to it later. Until the slit was found this was a homicide in name only. Dostie said when someone fully clothed is found buried in a clandestine grave it’s safe to assume homicide. Still, until the Walker autopsy there was no cause of death.

Walker asked Santa Barbara County coroner Robert Anthony, M.D., his opinion. Anthony said the slits were consistent with stab wounds.

Dostie now had a homicide and a cause of death.

Walker then took cranial measurements and delivered them to Stephen Ousley, Ph.D., at the Smithsonian Institution’s anthropology department. Ousley used a beta version of Fordisc 3 software he developed (with Richard Jantz, University of Tennessee) that uses sophisticated statistical procedures called discriminant function analysis to find the most morphologically similar groups to an unknown individual using only skeletal measurements. The technique has often been used to reliably estimate tribal identity of Native American remains for the Repatriation Office. Walker is a member of the Repatriation Review Committee.

The results indicated the victim had significant Native American ancestry, confirming DNAPrint’s analysis.

NEW FORENSIC GROUND
New DNA extraction methods and growing DNA databases can provide forensic insight into a person’s heritage and lifestyle, although few of these technologies have yet found their way into police crime labs.

Dostie is effuse, almost evangelic, about getting the word out to the law enforcement and forensic communities about the results he’s seeing.

“I don’t want attention, I want the case solved,” he said. “The guys that do a hundred more cases than I’ll ever do need to know what we’ve done here, that none of this is forensically routine.”

Next, Walker suggested Dostie contact Henry Erlich, Ph.D., director of research at Roche Molecular Systems (Alameda, CA), to have the victim’s human leukocyte antigen genes, or HLA, analyzed. HLA loci are the most polymorphic genes in the human genome. There are four types of HLA (HLA-A, -B, -C, and -D) expressed on surfaces of white blood cells. Erlich was able to extract only a B-type from the available DNA but this was sufficient to genotype two homogenous haplotypes (two closely linked alleles found on the same chromosome) – a condition extremely rare in most human populations but common among Native Americans.

Erlich’s conclusion: the decedent was a Mexican or Central American.

The search narrowed.

Walker then surmised that the victim was probably an immigrant from Oaxaca, from which many of the workers from California’s Central Valley have migrated. In order to substantiate his suspicion Walker wanted to know whether she ate corn, as in tortillas. He asked geochemist Henry Schwarcz, Ph.D., McMaster University, Hamilton, Ontario, to work up an isotope profile.

YOU ARE WHAT YOU EAT
The ratios of carbon (13C/12C) and nitrogen (15N/14N) isotopes differ slightly in different foods. Thus, it is possible to determine some aspects of a person’s diet by comparing the corresponding isotope ratios of food samples. For instance, the 13C component of hair, which is made largely of the protein ker-atin, reflects the 13C content in the protein of the food eaten.

This was the first time Schwarcz had tried these techniques on contemporary human bits. Normally, Schwarcz works with ancient human remains. The adage – you are what you eat – is true, whether you lived last year or 2,000 years ago.

An analysis of carbon and nitrogen ratios on samples of the victim’s hair was performed using an isotope ration mass spectrometer. Separate analyses were done of the scalp-end and hair tips to see whether there had been any change in diet over the last months of life.

Schwarcz concluded that over the last 16-18 months of life (the length of her hair) her diet included 57 percent maize (corn), 15 percent higher than the typical American diet. (The American diet is high in maize due to the widespread use of corn as animal feed in the production of meat, poultry, eggs, and dairy foods – the main sources of protein in the domestic diet.) However, it is not possible to determine where the maize she consumed had been grown.

Therefore, an isotopic analysis of the victim’s teeth and bone was done, using the isotopic ratio of oxygen to attempt to determine the geographic origin of the water she drank. Traces of oxygen isotopes from drinking water, known to differ by latitude, are deposited in teeth and bones.

Schwarcz’ data imply that during the last decade of her life the victim drank water found only in southern Mexico —more specifically, in the state of Oaxaca, near the Pacific coast. The search narrowed again.

INDIAN DNA
Walker wanted Dostie to run the victim against existing Native American mtDNA databases.

Abundant amounts of mtDNA are found in all human cells, making it easily extractable even from ancient remains. Because it doesn’t recombine with other DNA and is passed down only by mothers, scientists use mtDNA to isolate maternal ancestry

Walker sent the detective to David Glenn Smith, Ph.D., a University of California, Davis biological anthropologist. Smith maintains a database of 3,000 mitochondrial DNA samples of dozens of different Native Americans tribal groups from Alaska to Argentina that he uses to trace the ancient movements of people over the past 150 centuries.

Almost miraculously Smith found a match.

“The match was from a Zapotec Indian woman in the small village of San Mateo Macuilxochitl in the valley of Oaxaca, in southern Mexico,” Smith said. The woman’s name is Apolo-nia Mendoza, although in a subsequent interview with investigators she claimed no relationship to the victim.

The San Mateo sample was collected in 1994 by William Klitz, Ph.D., a UC Berkeley public health researcher. Klitz took blood samples from 33 Oaxacan villages, the mtDNA of which was eventually added to Smith’s Davis database

Matching mtDNA means the two women – Mendoza and the Mammoth Lakes murder victim – have a mother, grandmoth er, or great-great-great-grandmother in common. However, DNA experts warn that a mtDNA match is not to be interpreted as a unique individual fingerprint. While mtDNA of a specific pattern will be found among female descendants (and single generation males), if that pattern has been in the population long, apparently unrelated members of the population may share the type.

Nevertheless, the search beam now fell on that Oaxacan village. Dostie’s instinct is to eliminate most nearby villages as candidates, that mtDNA is probably village-specific. Linguists say 50 Zapotec dialects exist, and that people living only 20 miles apart cannot speak to each other. “People tend to marry people they can talk to,” Dostie said

ABOUT FACE
At about this time Dostie arranged to have the victim’s face reconstructed by Betty Pat. Gatliff, a noted Oklahoma forensic artist who specializes in 3D facial reconstructions using nothing other than the skull and clay. Gatliff spent about three days recreating the face.

When Dostie saw the resulting photographs he was aston ished at how closely the reconstruction resembled police draw ings of the victim by a Los Angeles Sheriff’s Department forensic artist from descriptions taken from U.S. Forest Service Visitor Center employees who may have seen the victim and her husband the previous fall. Gatliff had not seen the police sketch.

The photograph and police sketch were printed on flyers and distributed to Oaxacan-immigrant leaders in Los Ange les to be posted in business windows. One community leader, Ray Morales, president of the Oaxacan Businessman’s Association, travels frequently to Oaxaca. Dostie asked Morales if he would take some flyers down. Morales has done more than that. Not only has Morales shown the flyer personally in Oaxaca, he has even taken DNA samples of principals, with kits provided by the California Department of Justice.

Since being seduced by Dostie’s benign charm, Morales has made four trips to Oaxaca on Dostie’s behalf.

On his second trip the woman on the flyer was identified as Barbara Pacheco Santiago by her stepmother, who had not seen her for over seven years. Santiago’s biological parents have been dead for many years. The stepmother said Santiago had two sons, neither of whom has been located.

Morales has also learned that Santiago’s full sister, Rosa Pacheco Santiago, lives in Chiapas, address unknown. Rosa’s three daughters do live in Oaxaca, but according to Morales have no contact with their mother and want nothing to do with her after being abandoned in childhood. Morales, nevertheless, was able to obtain a DNA sample from one of the sisters.

At this point, positive identification of the victim is a numbers game. John Tonkyn, of the California DOJ DNA lab, said the more people maternally related to Barbara Pacheco Santiago that can be located the better chance of a definitive match. Dostie said the Holy Grail would be DNA from Barbara’s children.

TOOTH OF THE MATTER
Meanwhile, back in Santa Barbara, Walker recommended trying another technology that he thinks might provide additional, confirming proof of identity. This one is called Tooth Cementum Annulation, or TCA.

Cementum is the calcified tissue that surrounds the dentine and forms the attachment site for the periodontal fibers that link the tooth to the alveolar bone. New layers of cementum are laid down on tooth roots annually.

TCA is normally used to determine age at time of death of skeletal remains. The technique is based on microscopic images taken of toothroot cross sections. In a process similar to counting tree rings, age is then estimated by manually counting the incremental lines of cementum, then adding the chronological age at assumed point of tooth eruption.

An Italian researcher, Ursula Wittwer-Backofen, however, believes TCA can indicate more than age. She thinks the rings also indicate when someone has given birth, that traces left by the stress placed on the body by events like pregnancy and childbirth can be found in the rings.

“If we get the right age and the right number of births at the right intervals, then I think it will pretty much nail it,” Walker said.

Whether Barbara Pacheco Santiago’s identity is confirmed through some combination of DNA, BGA, HLA, or TCA, or whether the moldering remains resting in boxes on lab shelves and evidence rooms turns out to be someone else, one thing is certain. Whoever she is, she is no longer alone. Her cortege is led by a small town police detective and a distinguished anthropology professor. Like the victim’s watch, they are still running, determined to learn her identity, and then apprehend her killer.

Douglas Page writes about forensic science and medicine from Pine Mountain, California. He can be reached at douglaspage@earthlink.net