NOTE: This story contains sensitive images of human remains.

The young man was alive when he was left in the desert near Green Valley, Arizona. Perhaps he was making his first journey across the U.S.-Mexico border, or maybe he was a recent deportee. It’s possible his parents or brother or girlfriend were still waiting to hear that he was safe. But by last week, when he turned up at the Pima County Medical Examiner’s office in Tucson, Arizona, he’d been dead for approximately two months, and all that remained was a partial skeleton — missing its ribs, arms, hands and feet — some torn clothes containing six 100 peso bills and a pre-paid Visa charge card, and one battered red sneaker, an Air Jordan.

Forensic anthropologist Bruce Anderson inspects a skull belonging to an undocumented border crosser. The process of identifying remains can be difficult without funding and family support for DNA tests. Credit: Simon Asher for High Country News

In his brightly lit Tucson lab, the forensic anthropologist lifted a sun-bleached bone from a gurney and turned it in his hand, indicating an almost imperceptible scrape mark where a coyote had chewed it. Bruce Anderson, a tall man with a tanned face, slicked-back dark hair and mismatched scrubs, was fairly sure he knew the man’s identity, even without an identification card. Relatives back in Guatemala had convinced Aguilas del Desierto, or Desert Eagles — a volunteer group, composed mostly of immigrants, that does search-and-rescue work in the desert — to look for the man in the last place he was seen alive. These remains were found in the right location along with that red shoe. And the man had had an unusual set of extra canines; the teeth were gone by the time Anderson examined him, but the double sockets remained.

Anderson, who became a forensic anthropologist in part because he loved puzzles, worked through the evidence patiently. He carved a rectangular two-inch section of bone from the man’s leg to send for DNA testing. Anderson would ask the Guatemalan foreign consulate in Tucson to track down relatives in Guatemala and swab their cheeks for DNA samples, and to pay for a DNA comparison. “Even though we think it’s a good chance that this is a Guatemalan man who was missing two months ago, we still just can’t use a double tooth and red shoes as proof, so that’s the plan right now,” he told me, as we gazed at the person’s remains. But the plan could fall apart, if the likely family declined to provide DNA samples, or if the Guatemalan consulate couldn’t pay for the lab work. And even if Anderson ultimately solved this puzzle, there would be others: The same day they found the man with the red sneaker, Aguilas del Desierto discovered two other dead men.The number of undocumented immigrants trying to enter through the U.S.-Mexico Borderlands has fallen in the past decade to 1970s levels. But the number who die in the desert persists, so researchers and local officials have had to develop new methods for identifying their remains.

In the past, most people entering the United States illegally from Mexico have been Mexican. Over the last several years, however, more undocumented Mexican migrants have left the U.S. than entered. Instead, Central American families and unaccompanied minors fleeing political upheaval and gang violence try their luck in the Southwest’s unforgiving deserts. It’s not surprising that many die; for more than two decades, the United States has had a policy — “Prevention Through Deterrence” — that funnels people away from cities such as San Diego and El Paso and into the harsh Sonoran desert.

In The Land of Open Graves: Living and Dying on the Migrant Trail, Jason De León, a University of Michigan anthropologist and director of the Undocumented Migrant Project, cites federal documents showing that Customs and Border Protection (CBP) knew that more people would die as a result of the policy. Indeed, the combination of NAFTA, which forced Mexican farmers to seek work far afield, and Prevention Through Deterrence caused border deaths to skyrocket in the early 2000s. Last year, more than 300 deceased migrants were found in the Borderlands.

Anderson studied forensic anthropology in the 1980s because he wanted to help solve crimes (his father was a police officer); today, his office investigates unexplained deaths and the deaths of unidentified people found in most Arizona counties. “In 2000, there still weren’t as many migrant deaths,” he said recently. “We still didn’t know what was on the horizon.” Previously, one or two dozen deceased migrants would end up in the medical examiners’ labs each year. At that rate, the office could stay on top of identifying them. In 2000, the body count jumped to 74, and by 2002, it was 147. For the past 17 years, it’s averaged 166. Now, the office does triage, working on identifications according to how likely they are to make a match.

Remains that turn up with an identification card of some kind go to the front of the line, ahead of, say, a single weathered shoulder blade. Just recently, the office identified a father who perished in the desert in 2005, whose remains were not discovered until 2010.

“I don’t think anybody anticipated that a few governmental actions would cause people to have to cross in Arizona, and not cross in California or Texas,” Anderson said. “That crossing in Arizona is what led to most of the 3,000 deaths over the last 20 years.” In 2017, approximately 41 percent of border-crosser deaths occurred in Arizona.

Already in 2018, the remains of 80 migrants have been found and mapped in southern Arizona. The U.S. policy of “Prevention Through Deterrence” pushes people to the most remote and dangerous desert crossings, such as on the Tohono O’odham Nation’s land and Organ Pipe National Monument. Credit: Courtesy of Humane Borders, Inc. and the Pima County Office of the Medical Examiner

To cope with the high number of migrant deaths, researchers have had to change their methods — learning to identify the ancestry of skeletal remains of people who were Latino or Indigenous, for example. Historically, U.S. forensic anthropologists trained on the remains of whites, blacks and Native Americans. Still, the desert takes a toll. Within hours of death, the sun can discolor a person’s face so badly, the office will not show even a photograph to possible family members. And unlike many Americans, most migrants come from marginalized populations and lack dental records from health-care practitioners. “It’s almost impossible to identify people from traditional methods,” Anderson admitted. His office struggles to use fingerprints, which distort as they dry out, tattoos or the cosmetic dentistry known as “grillwork” to make identifications.

There’s no way to know how many people die crossing the Borderlands and are never found. Even when human remains turn up, they are desert-ravaged: scavenged and scattered by animals, sometimes more than 80 feet away; weathered by sun, mummified by heat. Encounters during the journey have an impact, too: People may be robbed of possessions that would help with identification, or be injured in a way that leaves lasting marks on bodies and bones. Indeed, disabling injuries are one reason that people are abandoned by others in the desert.

Fortunately, forensic DNA analysis methods have vastly increased the potential for identification: Today, researchers can extract and match DNA samples from just a single tooth or bone fragment. Nonprofits such as the Tucson-based Colibrí Center for Human Rights and the Argentine Forensic Anthropology Team work to persuade worried family members, who may be undocumented themselves, to provide DNA samples. The organizations sometimes help the medical examiner’s office pay for the analysis if they believe they are close to making an identification. In return, family members may get answers. “It’s horrible news, but that’s news that’s owed to the family,” Anderson said. Since 2000, some 375 people have been identified through DNA analysis. With enough funding, more people would be.

There are times when DNA matching is not an option. In some cases, remains may be too old or weathered to provide samples. More importantly, the examiner’s office needs DNA samples from surviving maternal family members in order to make a match. “We know that’s not going to happen in all cases,” Anderson said. “Some families are too afraid, some families don’t know where to look, some families are decimated, some families may not even exist anymore for these men and women.” Often, Indigenous families have fewer resources, don’t speak Spanish and don’t trust the Mexican government enough to file a missing persons report. According to a 2017 study that Anderson coauthored, this means that unidentified migrants with Indigenous roots are even less likely to be identified than people with more European ancestry.

Some families hesitate to help because they dread what they might learn. “They are afraid to believe the person is dead,” Anderson said. “They would rather believe the person is incarcerated, or a slave, or anything other than dead.” But De León contends that such a drawn-out period of wondering whether someone you love is alive is itself traumatic. If this man were successfully identified as Guatemalan, he could be shipped home for funeral services, or be buried or cremated in the United States.

When people are identified, it brings a turmoil of emotions, including for the researchers. “As a man who’s lost two brothers and a father, I don’t want to revisit the pain of a loss,” Anderson said. “What most of us in this line of work do is construct some kind of a metaphoric wall and stay on the postmortem side. We rely upon that wall and pass information over that wall: Colibrí passes a missing person’s description to us, and we pass a decedent’s description to them.” When the collaborators believe they’ve made an identification, the nonprofit notifies the family. This helps Anderson and others in his line of work remain emotionally detached — which helps them keep going. “If I start crying on the phone with the father of a dead boy, I am going to have to go home and not be able to work the rest of the day,” Anderson said.

In cases where genetic matches aren’t possible, researchers are adapting forensic anthropology methods — many of which were developed at research centers in the humid environments of Texas and Tennessee — for desert conditions.

A key part of that work is accounting for scavenging. “We know that vultures, coyotes are huge parts of this ecosystem,” Shari Ex, a forensic anthropology graduate student from the University of Tennessee who conducts research with De León, said. Even domestic dogs will eat human remains. Ignoring scavengers can lead to misdating, such as when the appearance of bones is taken as proof that remains have been there for a long time. In the desert, animals sometimes pick a person apart incredibly quickly, revealing bones within 24 hours of death. By understanding scavenging, Ex hopes researchers will be able to develop a better scale for dating human remains found in the desert. Knowing when a person died can be crucial for speeding up the identification process by eliminating older matches.

Forensic anthropology graduate student Shari Ex studies the remains of a pig 10 days after placing it in the Sonoran desert. The clothes make the work more accurate–and remind researchers of the human relevance of their work. Credit: Maya Kapoor/High Country News

Researchers began studying decomposition in the desert in 2012. But Arizona lacks facilities for the use of human cadavers, so the researchers use the bodies of pigs, donated for the cause. This summer, the local farmer who raised the four pigs that Ex and other researchers studied brought them to the field site alive and put them down himself. “It was actually a very emotional experience to share with him,” Ex told me. “Before he put them down, he said to the pigs, ‘You’re doing a great thing, you’re contributing to something very important.’ ” Ex and other researchers get mixed responses to their studies from the local community. For that reason, she said, “It was really moving to have someone like that whose job has nothing to do with this, but who’s kind of emotionally invested in the work.”

Though pigs aren’t perfect substitutes, they have important similarities to humans, including fat distribution and torso size. This is the third summer that researchers have left several dead pigs in the Sonoran desert. Then they watch what happens, making twice-daily visits to note observations, as well using remote cameras to record scavenging activity and drones to photograph the area.

In late June, 10 days after the pigs were left in the desert, I joined Ex — who wore a long-sleeved purple shirt, beige hiking pants, a sunhat and a tiny silver skull earring — as she inspected them. The researchers had placed the pigs in a sun-beaten, dusty Arivaca, Arizona, backyard carved out from the surrounding desert shrubland. Dark hills bunched in the distance, framed by blue sky. They had dressed two of the four pig carcasses in tiny clothes and shoes, to see how that would affect scavenging and decomposition, before placing the animals on the flattened brown grass and dirt. The homeowner, who had given the researchers permission, was on vacation. For shade, researchers sat on the patio of the brick ranch-style house, watching their drone zip overhead.

While work with human remains in a sterilized lab can be very clinical, these pigs were decomposing in a place where people go missing and die. “It makes the (emotional) separation a little harder,” Ex told me later. At the field site, Border Patrol aircraft occasionally passed overhead as the temperature climbed toward 100 degrees. Arivaca is located only 11 miles from Mexico, and Spanish-language radio broadcasts here warn would-be migrants not to risk a crossing: “You’re worth more alive than dead. … Don’t put your life in the hands of someone else.”

By mid-June, flies swarmed the researchers as they got out of their cars. The smell of decay pervaded the site. Where the unclothed pigs had been, now only stained earth remained. Scattered ribs and other bones gleamed in sunlight or hid under shrubs many feet away. The clothed carcasses, meanwhile, seemed to have mummified and were somewhat intact, though their faces and stomachs were torn and gnawed. One pair of tiny blue sneakers left behind by scavengers was a poignant reminder that children also try to cross the desert.

And yet pigs are pigs, not people, and the sight of rib bones and meat — however fetid — can stir something primal, too. “It’s a weird thing. Some people go home from this craving meat,” Ex said.

The oversweet odor of rotting meat can seem to penetrate a person. For days after I left the site, the scent would rematerialize, a phantom reminder that the United States is currently conducting an ever-growing experiment in human survival in the Arizona desert, and that at any given moment, people may be dying because of it. “The bigger picture here is that each year, hundreds of people die in the desert,” Ex said, “and those numbers are really just the people who are accounted for.”

This year, the combination of record hot, dry weather conditions and the growing militarization of the U.S.-Mexico border menace migrants even more. As of this writing, 80 unidentified border crossers’ remains have come to Anderson’s office this year. “There are things that our government has directly done to basically give these people no choice but to try to come here,” Ex said. “If we can’t get justice for these people, then the very least we can do is to figure out who they were, and to give their remains back to their family to attempt to — ” She hesitated. “ ‘Closure’ isn’t the right word, because I don’t think that’s something that’s in play for the families of people who die in the desert, but, at the very least, giving them a little bit of knowledge is kind of the goal here.”

Note: This story has been updated to clarify the role of Shari Ex, a forensic anthropology researcher. 

Maya L. Kapoor is an associate editor at High Country News.  mayak@hcn.org  

This article appeared in the print edition of the magazine with the headline Naming the Borderlands’ lost.

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