Trial By Fire: How a Forensic Scientist Used A Pig Fry to Implicate the Mexican Government in the Disappearance of 43 Students


The breeders, ironically enough, euthanized the pigs execution-style, shooting them once in the head at close range. Depending on the day, they might slaughter as many as four at a time, lining them up like captured rebel militiamen, then hurriedly loading the carcasses into the back of a van, and racing off, coming to a halt minutes later on a gravel road at the edge of a dazzling green field in the Australian outback.

A dozen casually-dressed researchers greeted them as the van’s doors opened, unloading the hog cadavers with a certain, commando-like precision, methodically bundling them into thick, wool blankets, and extracting a single tooth from the pig’s mouth, which would enable easy identification later. University of Queensland Engineering Professor Jose Torero’s research team couldn’t afford to waste too much time; if rigor mortis stiffened the pigs’ muscles, it could affect the study’s findings and everyone was aware that there was a lot riding on the results of this experiment.

Two, and sometimes three researchers were required to lift and carry the pigs–150 pounds of slippery, dead weight–and hoist the carcass atop the makeshift funeral pyre assembled in the middle of the field. “As it turns out,” Torero said, “dead pigs are not easy to handle.”

And then the pigs were set alight.

Stoked with kerosene and heptane, the conflagration was immediate, the Kool-Aid orange flames leaping as high as four-feet high into the powder-blue morning sky. Once lit, Torero and his team stepped away to observe from a comfortable distance while a lone student–one of several experienced firefighters studying under Torero– minded the inferno.  Nothing was taken for granted: a circuit-board of instruments measured temperatures, weight, and body mass, a mammoth tray–roughly the size of two spread-eagled LeBron James’s arranged like a crucifix–collected the pig’s dissolving, viscous tissue, and a drone photographed the bonfire from above.

At first, the smell was familiar, almost pleasant, like a mid-summer backyard barbecue or bacon frying in a pan. But when the the flames breached the first layers of skin, and ruptured the pig’s’ intestines, a blood-curdling stench began to waft over the scientists.

“It was almost unbearable,”Torero said, redolent of raw sewage, and death.

But there was also something in the fetor of burning hog flesh that smells like victory, or better yet, justice, to Torero. This experiment, carried out over several weeks earlier this year ago in a patch of farmland near Brisbane, was akin to an exhumation, or perhaps better yet, a seance, raising the spirits of 43 young Mexicans slain two continents away to ask the question that has bedeviled an entire country since September 26th, 2014.

Each charred hog was a proxy for the 43 college students who vanished from a two-lane highway in the southwestern state of Guerrero on Mexico’s Pacific Coast. To this day, Mexico’s top law-enforcement authorities insist that rogue local police officers ambushed the caravan of buses carrying the nearly 100 students from an all-male teachers’ college in the city of Ayotzinapa to a memorial service in Mexico City, turned their captives over to a notorious drug cartel who took the students to a garbage dump in the neighboring town of Cocula, murdered them, and cremated their bodies in a leviathan heap of wood and tires doused with gasoline.

There are only two problems with the official story, or maybe three if you include the fact that practically no one in all of Mexico believes it. For starters, survivors of the attack say that their classmates were all taken away in marked police patrol cars, and witnesses place both army intelligence and federal police at the crime scene.

And secondly, an international committee of human rights experts reviewing the case invited Forero to view the site where the bodies were allegedly burned. After spending less than an hour on the ground in July of 2015, Torero saw no evidence of a fire of the size that would’ve been required to transform a trash dump into a crematorium that ran hot enough to disappear the bodies of nearly four dozen young men.

“…As scientists we are very often proven wrong, but this time we just couldn’t afford to be wrong.”

“The families of these 43 young men have suffered enough,” Torero said. “The last thing I would’ve wanted to do is to raise a stink where none is warranted and get this wrong. The stakes were very high.

As scientists we are very often proven wrong, but this time we just couldn’t afford to be wrong.”


Fire has long captured the popular imagination. Long before the advent of radio, bonfires used to serve essentially the same purpose as television does today, its mindless, spectacle providing numbing entertainment, strangely comforting, for hours on end, said John Lentini, a Florida fire scientist.

Owing largely to Western Christian values, the desecration of the human body has long been  viewed as something of an affront to God, bordering on blasphemy. “People wasn’t made to burn,” an African-American steelworker named James Hickman told Chicago police in 1947 after fatally shooting the unscrupulous landlord who set fire to his apartment, killing three of his eight children. A broad, coalition of African-Americans, Trotskyites, trade unionists and celebrities–including the actor Tallulah Bankhead– managed to win both Hickman’s freedom and a crackdown on landlords deploying arson as a tool for eviction.

The Peruvian-born, 52-year old Torero has long been fascinated with the substance of fire, beginning as an engineering student at the University of California at Berkeley, where he worked with researchers studying safety problems at the International Space Station. While doing his postdoctoral work at the European Space Agency, however, a 1999 tunnel fire in the Swiss Alps that killed 38 people, recalibrated the trajectory of his career. He began exploring fires that were less ethereal and closer to the ground, and had, what he describes, as “social impact.”

Following the 9/11 attacks, he interrogated the Twin Towers’ structural deficits with an eye towards improving skyscraper design. And in 2011, he investigated a fire that killed 81 inmates in Chile’s San Miguel prison. At issue was whether the prison guards were culpable for the deaths. After recreating the blaze using laboratory models, Torero and his team of researchers concluded that by the time the guards saw smoke billowing from the cells, the surface area of the padlock was too hot to open and the prisoners were already dead anyway. The real culprit, he concluded, was prison overcrowding.

Of the many admirers of Torero’s work in Chile was the human rights lawyer Francisco Cox, one of five independent experts convened by the Inter-American Commission on Human Rights to examine both the students’ disappearances and Mexico’s attorney general’s  handling of the probe. Cox’s  email led to a phone call in which Cox asked Torero if he would come to Mexico to have a look?

“Of course I was familiar with the case already,” Torero recalled. “They (the panel) had very limited resources. We agreed I was just going to visit the place and give them some advice.”

Arriving in Mexico City in mid July of last year, Torero was flown by helicopter to Guerrero, and driven in armored cars to the Cocula dump site. He was accompanied by Cox and a deputy attorney general and soldiers armed with machine guns. Torero understood that authorities were trying to intimidate him, but pretended that he didn’t.   

“Every move you made, there were people taking your picture with their cellphone,” he recalled. “I am a man of science; judging their personal motivations is something I tried to put aside. They really think that what they’re doing is right. So I tried to give them the benefit of the doubt,”

Still, it was clear almost from the moment he arrived at the Cocula dump what had, or rather had not happened there. “The car brings you to the top of the dump, so that you have to walk down to the ditch,” he recalled. “And the first thing you notice as you’re walking down this is that it is a  mountain of plastic, and the damage that should be evident from a fire of the size to cremate 43 bodies is completely absent. It just doesn’t exist.“

Most telling, he said, was the vegetation surrounding the dump. He would’ve expected an intense blaze to have resulted in singed foliage, and charred tree trunks in the immediate area, but as he inspected the site, snapping photographs, he could not find so much as a single tree with the tell-tale blackened bark.

“I knew then,”Torero said matter-of-factly, “ that no fire of any magnitude had happened here.”



Still, knowing something and proving it are two entirely different things.

With the Mexican government publicly questioning Torero’s findings, and credentials, he decided to interrogate their claims empirically.

“I had never been so insulted in all my life,” he said.

The approach he decided on is what’s known in the field of scientific inquiry as a reverse forensic investigation, meaning, Torero said, “that you can’t prove what happened, but you can certainly prove what didn’t.”

At issue, principally, was the question of just how much fire is necessary to  cremate 43 bodies, weighing an average of 140 pounds, according to population health statistics in Mexico. The human body is comprised mostly of water, which of course, is a fire inhibitor. But the skin, and its fatty layers underneath, also provide a fuel source. Where, exactly, was the tipping point?

“What we had to find out,” Torero said in a Skype interview  “is at what point does the body overtake the timber, and at what point does the timber overtake a human body?’

To get the answer, they turned to the pigs, which are widely known by forensic scientists as the best surrogate for human skin. The thickness of the skin, the layers, fat content and solubility are far from a perfect match with human skin, but similar.

Using the average weight of a 20-year-old Mexican male, Torero contracted with a local breeder to provide pigs of roughly the same weight. The irony of the arrangement was not lost. Under Australian and international ethics conventions, euthanizing animals requires a lengthy approval process, which of course, was far more consideration than any of the 43 disappeared received.

Using the average weight of a 20-year-old Mexican male, Torero contracted with a local breeder to provide pigs of roughly the same weight. The irony of the arrangement was not lost. Under Australian and international ethics conventions, euthanizing animals requires a lengthy approval process, which of course, was far more consideration than any of the 43 disappeared received.

In its final 500-page report, the human rights panel charged with investigating the massacre surmised that in commandeering the buses to attend a memorial service–a harmless tradition in Mexico–the students may have unknowingly boarded buses concealing trafficked heroin. Adding insult to injury was that the Ayotzinapa Rural Teachers’ College attended by the slain students was created nearly a century ago to expand opportunities for the area’s large, Indigenous population, and was widely-known as a hive of progressive activism.

On the other side of the world, Torero was hardly oblivious to the politics of the situation. You need not be a radical to recognize that the fissure between those who built Latin America and those who own Latin America yawns wide as an abyss. But he is, at his core, a man of science, and what truly offends him, he readily admits, is using “science to justify the unjustifiable,” such as Chilean authorities attempt to scapegoat the workers for their own mismanagement.   

Consequently, his preoccupation was identifying the equilibrium at which a pigs’ skin feeds an inferno rather more than it starves it.

“We started with one pig and started adding wood,” Torero said. The research team did this over several weeks, experimenting with different combinations of the number of pigs. The bonfires could last as few as two hours, or as many as 10.

But getting to the bottom of things only required 15 hog carcasses before Torero’s research team reached a definitive conclusion. Generating a fire needed to essentially consume all visible traces of a single, 150-pound pig, required 1,300 pounds of wood, or well over half-a-ton.

In other words, incinerating 43 human bodies that weighed an average of 150 pounds would require roughly 28 tons of wood.

“We do so much work up front that we have a good idea of what to expect going into the experiment,” Torero said. “Still, with fires this large, there’s always some uncertainty  . .”I was a little worried going into the experiment, not so much about my professional reputation but just about being able to bring closure to these families.

“It gave me a tremendous sense of relief to be able to say, ok, here’s what didn’t happen to your son. You can stop looking in that dumpsite for answers.”