Tainted Evidence: Mexico's Surprising Answer to Crime-Lab Corruption - OZY | A Modern Media Company

Tainted Evidence: Mexico's Surprising Answer to Crime-Lab Corruption

By Meghan Walsh


This is how you solve a murder. 

Except for a single wooden crucifix hanging from a nail, the crime lab’s morgue looks antiseptic, with stark white walls and silver-railed beds. I’ve been there for less than an hour when the medical examiner wheels in a body encased in wet garbage bags. With help, he hoists the mass onto a stainless steel body tray, and immediately, the crew goes to work, cutting the plastic away, one layer at a time, the way a child carefully pries the wrapping paper from a birthday present. It appears the victim, a late-20s male, was beaten, suffocated and then dumped in a canal. The cartels call these corpses regalos, or gifts.

A handful of plain-clothed investigators hover while the forensics workers dutifully collect evidence: snapping pictures, snipping hair samples, swiping under fingernails. The lead detective voices her displeasure that I’m here, but the guys in the lab coats just smile. She can stomp her feet all she wants, but this forensics lab, in Guadalajara, isn’t police turf. The son of God peers down from above; the badge has no jurisdiction here. 

Elsewhere in Mexico and in all of the United States, forensics falls under the strong hand of law enforcement. On the never-ending reel of CSI shows, agents dust for fingerprints in one scene and pull out the handcuffs in the next. Here in the midwestern state of Jalisco, it’s different. Specially trained civilians do the DNA testing, while police must keep their distance. It might sound like little more than a bureaucratic nuance, but this small detail packs a decent amount of reform. And it’s a model that has found purchase north of the border, as crime labs continuously come under new scrutiny for their dysfunction and the toll of botched convictions notches ever higher.

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The autopsy room at Instituto Jalisciense de Ciencias Forenses in Guadalajara can accommodate eight bodies at a time and is often full. 

Source Alex Washburn/OZY

In Jalisco, home to the cartel that last spring shot down a military helicopter with an RPG, venality runs deep and the violence is heinous: corpses cut to pieces, fingerprints burned away with acid, bodies stacked on top of bodies. Indeed, as the narco wars have reached new depths, it’s been hard to see any light through the blood and despair. But 18 years ago, amid recalcitrant corruption, officials decided to partition forensics from police and prosecutors, giving the Instituto Jalisciense de Ciencias Forenses complete autonomy. Independence, they believed, would prevent conflicts of interest, promote scientific integrity and restore public trust.

Sure enough, since the reorganization, the institute has become a beacon of pride, doing what others in Washington, D.C., and around the world haven’t been able to. Less certain is whether America, in the age of criminal-justice reform, is finally ready to take a few cues from its southern neighbor.


Forensics corruption doesn’t afflict only developing countries like Mexico, shot through with organized crime. The United States has its own litany of horror stories, many of them resulting from pressure to convict at any cost, even wrongfully. Last spring, the Feds admitted that over a two-decade period, one FBI forensics unit tainted every trial it testified in, including 32 cases that led to death sentences. Back in 2010, it came to light that North Carolina crime-scene investigators withheld or distorted evidence in more than 230 cases over 16 years — three resulted in lethal injection. An independent report cited “widespread lying, corruption and pressure from prosecutors and other law-enforcement officials on crime-lab analysts to produce results that would help secure convictions.” The list could go on. And on.

The problems run deep. For starters, there are no requirements — no degree, no special training — to become a forensic practitioner. American crime labs don’t require accreditation either. As Victor Weedn, chair of the Department of Forensic Sciences at George Washington University, says, the practice of forensics began with a detective in a closet with a microscope and, in many ways, never evolved past that. The tradition is not necessarily scientific. At IJCF, in contrast, most employees have Ph.D.s, law degrees or some sort of forensics background — and the institute offers bachelor’s and master’s degrees as well as ongoing training for all staff.

Then, of course, there’s bias. When lab coats and badges work side by side, there can be gentle pressure to sacrifice methodology for expediency — or, more blatantly, to confirm a suspicion. It’s not necessarily malicious. It’s only natural for the two sides to become intertwined and for scientists to begin to see themselves as prosecution witnesses rather than objective outsiders. A 2009 National Academy of Sciences report, Strengthening Forensic Science in the United States: A Path Forward, went as far as to call for the removal of all public forensics services from the rule of law enforcement and prosecutors’ offices. The Department of Justice and National District Attorney Association (neither of which responded to requests for comment) oppose the recommendation, as autonomy can come with unintended consequences. “There’s a lot of fear around this issue,” says Sandra Thompson, a law and criminal justice professor at the University of Houston and author of the book Cops in Lab Coats.  


Located in a charming neighborhood on the outskirts of the city, the IJCF is a beige, indiscreet complex that all the cab drivers know. Walking the paint-chipped halls turns out to be a four-hour excursion. One office after the next: explosives, polygraph, genetics, fingerprints, forensic psychology, financial fraud, cyber crime, chemistry, cartography, ballistics … the morgue, the den where they reconstruct skulls, the cove where they x-ray bodies, the wall-length freezers that store 72 corpses and are always full and for the past month have been guarded by two soldiers.

On a Friday night, well past happy hour, each of these departments still has workers hunched under fluorescent lights, staring at screens or pouring from beakers. But even at a time when most wouldn’t want to be working, everyone is stoked to talk about what they do and quick to make a joke. Even the lonesome guy who has been deactivating explosives and disassembling grenades for the past 17 years has a mischievous grin. You have to laugh, they say, when up to 10 bodies a day are coming in. It seems to work, considering that, over 72 hours, I met only one staffer who’d worked there less than 10 years.

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A member of the ballistics team shows off a variety of weapons confiscated at crime scenes. 

Source Alex Washburn/OZY

And then there are the peritos, civilian crime-scene investigators, witnesses to the worst of humanity. They work in teams of about seven. Twenty-four hours on, 48 hours off. During my visit, it just so happens to be one of the calmest weekends on the books. The first night, we sit in a bare room for 14 hours — a few desks with computers, a small TV, instant coffee — without a single call. They joke that I’m good luck.

The next night, around 2 a.m., we hear about a shooting. A young woman with a delicate side-braid and military-style boots grabs her toolbox and we speed off, lights blazing, toward a destitute barrio notoriously ensnarled in the cartel’s tentacles. The dirt roads are so rutted our Jeep Wrangler can barely navigate the steep, inky alleys. Once on scene, though, it’s the opposite of law and order. To the thump of banda rhythms, children run through the crime scene while the investigators go to work. The perito rolls a pedometer to measure distances, a man from ballistics searches with a flashlight for meandering bullet holes and casings, while another woman pulls out vials for DNA evidence. Just feet away, several guys continue wrenching on a car like nothing has happened. Because to them nothing of notice has happened. A solo shooting, especially one without a corpse, is everyday fare. 

Just before we got the shooting call, 24-year veteran Pablo Bernal Rodriguez pulled up photos on the computer, to a soundtrack of Enya playing in the background. The peritos can get nostalgic, in a way, revisiting past crime scenes, none more so than the day in 2012 when Rodriguez’s team got a call at dawn about a truck near the highway holding several dead bodies. Turned out they’d find three trucks and 32 dismembered bodies, a regalo from a rival gang. “It was overwhelming,” Rodriguez recalls. “All we could do was one thing at a time.” It would take the entire team 72 hours straight to complete their analysis.

In the past, Rodriguez says, investigators might have pressured them not to look into certain cartel-related crimes, or their findings might disappear into the abyss. Today, every case comes with a paper trail, and prosecutors have little choice but to follow it. Since the institute was established, in 1988, the number of cases in which a suspect is identified has increased 500 percent. Five men are serving life sentences for the 2012 highway bodies.


The situation north of the border is nowhere near as dire, and yet the idea of independent forensics might be starting to catch on. Crime labs in six states are not under the jurisdiction of law enforcement, according to data from the National Conference of State Legislatures. In 2014, Senators John Cornyn, a Republican, and Patrick Leahy, a Democrat, introduced legislation that would create a federal forensic sciences office and establish a committee of scientists to determine best practices. It also would put into place a checks-and-balances system and tether funding to credentials. (The bill is now stalled.) Several years ago, the District of Columbia moved its forensics operations into a new building and put it under the purview of its public health department. And Houston recently became the first and only jurisdiction to create a public-private corporation that, while government funded, answers to an independent board of directors, similar to the arrangement in Guadalajara. “If the Houston experiment succeeds in the way they hope it will succeed, it will be a shining example and maybe the catalyst we’ve needed,” Thompson says.

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At the scene of a shooting around 2 a.m., forensic investigators collect evidence as kids play among the crime scene. 

Source Alex Washburn/OZY

Houston’s troubles were long-standing: In 2002, the lab was temporarily shuttered because a decrepit roof had been leaking rainwater onto evidence for years. At one point, there was a backlog of almost 7,000 untested rape kits. Eventually, in 2014, the mayor ousted the Houston Police Department as overseer. Since then, the Houston Forensic Science Center and its director, Dan Garner, have collected a $1.26 million grant to purchase new DNA-analyzing equipment. Four of the office’s disciplines were recently awarded an elite international accreditation, and the rape kit backlog has been erased. Several months ago, a neighboring county decided to outsource all its crime-scene needs to the Houston lab. “The wake-up bell has been sounded,” says Garner.

Of course, it’s not all rainbows and solved murders — and independence is not a panacea. In its three years of functioning, D.C.’s state-of-the-art, $220 million lab has faced allegations of rampant errors, including poorly trained civilian technicians, out-of-date technology and bureaucratic dysfunction. (The lab’s representatives did not respond to requests for comment.) Law enforcement and labor unions have also protested the shifting of powers, in the States and around the world. Earlier this century, the U.K. established a government-owned, independent forensic company that some hailed as a global example. Yet, several years ago, police seized operations back under their control. Some argue that police-led labs are more efficient and better at getting resources. Others disagree with the idea that civilian investigators should have access to crime scenes. 

In the end, though, most investigators say the bureaucratic logistics aren’t nearly as complicated as navigating the emotional complexity of the job. Back in Guadalajara, as the sun sets behind the western mountains, I head out with several investigators to get a bite. But as we pull out, there’s a cluster of people outside the gate. Through the commotion I see an older man with his arms wrapped tightly around a younger woman, who is flailing in desperation. It’s the family of the young man whose body appeared in the morgue earlier in the day, wrapped in wet garbage bags. “That’s the hardest part of our job,” says Pedro Guerrero Haro, an 18-year veteran of the institute.


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