At Tennessee’s Body Farm, Mexican investigators learn how to dig up graves

at Tennessee’s Body Farm to dig graves



On a chilly fall morning here in eastern Tennessee, Raul Robles crouched alongside an open grave, surveying the bones his team had just unearthed. He was unusually relaxed and bowed his head to the salsa music from his phone as he measured and mapped the dirt-stained vertebrae and ribs.

Robles, 41, is used to much more harrowing conditions. Back in the Mexican state of Sinaloa, where he has excavated at least 500 clandestine graves during his 15 years as a crime scene investigator, he sometimes digs under surveillance from a drug cartel. The lookouts arrive on motorcycles without plates and turn off their lights. They say, “You have two hours to complete this, or else,” he added. When that happens, he is forced to take the contents of the gravesite and place it on a tarp. He then returns to the laboratory to finish his work.

More than 93,000 people across Mexico are officially classified as missing — a staggering total that points to a crisis of not only violence but also forensics.

Crosses mark a mass grave in Tijuana.

Unidentified bodies are buried in a mass grave in Tijuana in 2018.

(Gary Coronado / Los Angeles Times)

In recent years there has been a growing recognition that many of the missing may be in government custody — their bodies scattered among the tens of thousands of corpses that have passed through morgues without being identified and then buried in common graves. Mexican authorities have pledged to identify human remains they are taking care of.

That is why Robles and 23 other Mexican crime scene investigators, forensic archaeologists and morgue workers spent five days last month at the University of Tennessee’s Forensic Anthropology Center, a world-famous research center better known as the Body Farm. For more than 40 years, researchers at the farm had been setting fire to donated bodies, immersing them with water, breaking them down, and then rolling them up in carpets before putting them in cars trunks. This was all in an effort to discover more about how different corpses decompose.

Typically when they host visitors at the farm — a sloping 3-acre section of forest strewn with about 100 bodies in various states of decomposition — the researchers offer words of caution. Dawnie Wolfe Steadman advises visitors to take deep, slow breaths. If you feel you might faint, you can sit on the ground. The Mexican visitors were not trained but did not have experience and needed no warnings.


In 1977, forensic anthropologist William Bass was summoned to a cemetery in Franklin, Tenn., where police had discovered what they assumed was a recent murder victim.

Bass reached the same conclusion. He estimated that the man was dead for less than one year based on his body’s condition. He was more than 100 years away.

The body turned out to be that of a Confederate soldier felled in the Battle of Nashville in 1864. Grave robbers took the body from a cast iron coffin to prevent it from decomposing.

It was a moment of great transformation for Bass. He realized that science knew very little about the process of bodies decaying.

Soon, the University of Tennessee gave him access to a former dump site located behind the medical school for experiments on donated corpses. The university sealed the area with razorwire after community protests. Bass and his research team operated in relative anonymity for many years. Then in 1994 crime writer Patricia Cornwell published “The Body Farm,” a thriller loosely inspired by the facility, earning it both fame and a new nickname.

Today more than 5,000 people have registered to donate their bodies when they die. The farm’s researchers regularly act as experts witnesses in murder trials or conduct trainings for FBI agents.

When the U.S. asked about sending Mexican teams to the farm in order to learn more about forensic excavation, they quickly realized that their usual course of action would have to be modified.

Investigators at a homicide scene in Acapulco.

Crime scene investigators at a homicide scene in Acapulco, Guerrero, in 2019.

(Gary Coronado / Los Angeles Times)

Simply put, Mexican investigators work under some of the most chilling and challenging conditions in the world.

” One grave might contain three heads and five legs,” Sandra Macias Gutierrez from Colima said, over lunch of pizza and soda, during a break in class. “The narcos like to dismember the bodies they’ve already killed to make identifications really hard.”

Many parts of her country have not been at peace since 2006, when then-President Felipe Calderon declared war on the drug cartels, and killings and disappearances soared. Sometimes the narcos and sometimes the corrupt police were responsible for inventing more brutal forms of murder.

Many Mexicans closely associate the drug war with the United States, not only because of the vast American appetite for illegal drugs and the large numbers of firearms spilling south over the border, but also because the dramatic rise in violence coincided with a controversial and costly cross-border security partnership called the Merida Initiative.

At the behest of Mexican President Andres Manuel Lopez Obrador, who says the warlike approach to drug trafficking turned Mexico into a “graveyard,” a new bilateral agreement is being negotiated. Officials from the U.S. say that they will not be focusing on the militarization of Mexico and instead adopt a holistic approach to public safety. This includes funding drug treatment, targeting gun traffickers and funding forensic training programs such as the one that brought the Mexicans into Tennessee.


Tensions that in recent years have strained the U.S.-Mexico relationship at the highest levels — including a claim by Lopez Obrador that the U.S. fabricated a drug case against a former Mexican defense minister — were nonexistent on the farm. The students and teachers were bonded by their love for bones. They gathered around a set ribs that had been fusing together after their owner was diagnosed with a rare condition.

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And they commiserated over the hit television show “CSI: Crime Scene Investigation,” which they agreed had spawned inaccurate expectations about the speed of forensic investigations. The students spent their first two days in class and took their seats in a quiet ballroom at the Hilton downtown Knoxville each morning for many hours of lectures. They covered decomposition science and forensic entomology. This included learning how to estimate the time of death by identifying the insects present. They listened attentively to the Spanish-speaking instructors explain the best methods to recover evidence from burned bodies.

By day three, they were ready for the dirt. They rode in vans across the town to the Body Farm.

Two people sort bones on a blue tarp.

Raul Robertles was right. He was one of the two dozen Mexican crime scene investigators who attended a University of Tennessee course.

(Kate Linthicum/ Los Angeles Times )

After donning puffy white hazmat suits and blue booties, they walked the grounds. They passed many bodies that were mummified with leather-like skin still clinging on to their ribs. Some were still covered with blackened flesh. To protect themselves from hungry raccoons, most of their hands and feet were covered in red plastic netting. The cool, humid air made the smell of decay much milder than in the summer heat. The Mexicans split into four groups, with each team digging a fake grave over the next days. A typical course involves burying a single body. To replicate Mexican situations, researchers prepared complex graves. They disassembled several skeletons and buried them with other evidence.

Several students quickly created a grid using stakes and string at one burial site. It was located next to a wooden scaffold that researchers use to simulate hangings. They began to remove the earth and revealed a necklace, a gun, and then a femur.

Several stretched out on their stomachs as they swept away dirt with their fingers and tiny brushes. They stopped every time they discovered a new layer, the deepest being about 4 feet deep.

Researcher and student at the Body Farm

Joanne Devlin from the Body Farm digs through dirt alongside Isaac Aquino Toledo (a forensic archeologist hailing from Hidalgo, Mexico).

(Kate Linthicum/ Los Angeles Times )

“We want to preserve the spatial relationship of different pieces of evidence with the body,” said Joanne Devlin, an associate director of the farm, who explained that preserving the specific timeline of when things were buried would be crucial for building a case later. The Mexicans also shared their tips.

Isaac Aquino Toledo, 43, used small wooden stakes to hold the evidence in place while he worked, an unusual trick Devlin thought was genius.

“Sometimes I find the footprint of a shoe and then I find that same shoe on the victim,” said Aquino, a forensic anthropologist from the state of Hidalgo. “It’s usually because the killers made the victim dig their own grave.”

Later, as he was digging, he sighed: “I wish there was a better way to remove this dirt.”

“We need a forensic dustbuster,” Devlin said. “Invent one! You can retire!”

Along with teaching the best practices, the researchers demonstrated some shortcuts.

” If you don’t want to measure each bone in a grave, or it’s too dangerous, this method is for you,” Mary Davis told a group students. She showed them how instead of measuring them individually, they could draw them on a grid.

Carolina Montes, a forensic analyst from Tepic, in western Mexico was digging through dirt using a sieve.

She held a small, off-white object which looked almost like a pebble.

” “Is it cartilage?” asked a friend. Montes stated that he thinks it is a tooth, and deposited it in a bag with evidence.

Montes, 26, said most forensic training programs in Mexico didn’t teach much about excavation and that people mostly learned on the job. It was much easier to excavate the mock grave at Body Farm than it was back home.

” “The grave isn’t very deep and dirt is easy to find through,” she stated. “We’re used to graves with 10 people in them.”


When her students had finished their work, one of the teachers, Lee Meadows Jantz, took the bones they had recovered and laid them on a blue tarp. They would be cleaned, boxed and put in storage for future study along with roughly 1,600 other skeletons.

Then she asked her team a question: “Have you ever buried a body?”

Several people broke out in laughter — until they realized she was serious.

This is a routine that is performed at the end most Body Farm training courses. Meadows Jantz found a partially decomposed corpse in her waiting room, wrapped in a sheet and ready to be placed into a mock grave.

The Mexicans placed it under a barren honeysuckle and a few pieces. One shouted, “Throw in another shoes!”

In spring, the honeysuckle would blossom with white flowers. It would turn deep red in the late summer. The body would eventually become bones after several seasons. This will provide clues for the other students.

That afternoon at a graduation ceremony at the hotel, the director thanked the students, telling them, “I feel that we have learned just as much from you.”

Each was given a small bag packed with trowels, brushes and other tools of the trade — items that are in short supply back home.

Often, Mexican forensic investigators have to buy supplies themselves because their departments are so underfunded. Local families often purchase tools to search for their loved ones.

The collectives, which alert authorities to the location of possible graves, often stand watch during excavations, praying out loud for their sons or daughters to be found even as they dread such an outcome. Investigators often work to the sounds of crying mothers.

” “It’s very difficult,” Montes stated. “But I do this job so I can help people get back to their homes.”

How you deal with these emotions is not something that the Body Farm teaches.

Cecilia Sanchez in The Times’ Mexico City bureau contributed to this report.

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