When an investigator arrived at the ADX shortly after the murder to interview the other prisoners who’d been in the rec yard that day, he got no answers. No one spouted a lie or even a perfunctory “fuck off.” One by one, the men sat down across from the investigator and refused to talk. At most they uttered “not interested.” Several inmates offered only blank stares.

As staff lifted the inmate onto a gurney and wheeled him at speed to the prison’s medical center, Gladbach began chest compressions. Someone else called local paramedics, who arrived at 8:50 a.m. They spent 22 minutes trying to revive the man with CPR, intubation, and epinephrine. Nothing worked. They would have declared him dead on the spot, but federal policy required that he be transferred to a hospital before that could happen. So the paramedics loaded the man into an ambulance and drove into Cañon City, the nearest town with a hospital. Just after 10 a.m., an ER doctor called time of death.

In her six and a half years at ADX Florence, Gladbach had gotten to know many of the inmates well, but she couldn’t tell who the man was. The skin on his face was blackened from bruising, and his features were swollen from extensive blunt trauma. One signal of brain activity is the responsiveness of pupils to light, but Gladbach couldn’t pry the man’s eyelids open to perform the test.

When officers arrived at the rec-yard gate, the inmates looked relaxed, as if nothing had happened. Some even continued exercising. ADX policy required a three-to-one ratio of staff to inmates before officers could enter the area. To meet that standard, guards had to pull a few men out of the yard. They ordered everyone to drop onto their stomachs with their hands above their heads, then called an inmate’s name. He got up, walked to the gate, and put his hands through a slot. The guards secured cuffs on his wrists before opening the door and pulling him inside. Protocol demanded that the officers do this one prisoner at a time.

From their outpost, Guadian and Aragon watched. The cameras picked up video but no audio. When a few guys clustered together, the officers zoomed a camera in on the inmates’ hands and feet, looking for the surreptitious exchange of weapons or contraband. They scanned for any unusual or sudden movements. A little over an hour into their shift, the officers hadn’t spotted anything noteworthy.

The prison is a veritable fortress. Located about an hour south of Colorado Springs, it’s designed to keep inmates caged and isolated. ADX Florence keeps every prisoner in solitary confinement for upwards of 20 hours per day. For someone to get out, he would have to contend with the thick concrete walls of his cell, remote-controlled steel doors, razor-wire fences, attack dogs, and armed guards.

The feed came from cameras positioned in the prison’s recreation yards. Guadian could control them from a computer at his post. It wasn’t exciting work, watching grainy video for hours at a time, but it wasn’t all that taxing either. The Administrative Maximum Facility, or ADX, ran like clockwork. Altercations among inmates were exceedingly rare, and none had been deadly. No one had ever tried in earnest to escape. On rec ops, Guadian had to stay alert in case a rare infraction occurred.

Guadian had made a habit of arriving early for his shift; he never wanted to rush any tasks. The correctional officer walked through a metal detector and past the guards at the front entrance, then down a quiet, sterile hallway illuminated by fluorescent bulbs. At the complex’s administrative hub, he signed out a set of keys for the video-monitoring room, a small office outfitted with a desk, a couple of swivel chairs, and about two dozen small TV screens. Guadian ran through a checklist. He switched on the monitors; they were all working. Check . He inspected the VCRs connected to the screens; they were loaded with tapes. Check . The tapes were recording properly. Check .

Near dawn on April 21, 2005, José Guadian arrived at the federal prison where he’d worked for more than a decade. The bland, low-lying complex in Florence, Colorado, was located off a stretch of State Highway 67, a two-lane road running like a jagged vertical scar through the middle of the state. To the north and west, Guadian could see the Rocky Mountains towering on the horizon. They stood in majestic contrast to the land around the prison. Sun-bleached grass, scattered shrubs, no trees to speak of—it was lonely terrain.

Torrez was in his sixties by then, with four grandkids back home. At the ADX, he gained a reputation as one of the graying old guard. He moved slowly when officers escorted him down a hallway or up a flight of stairs. Sometimes he had to steady himself against the prison’s walls. Andres told me that, at some point, his father had suffered a stroke.

Torrez’s past caught up with him in 1999, when he was charged under RICO for a range of allegations involving homicide, assault, extortion, and possession of drugs and weapons. According to a member of the Metropolitan Violent Gang Task Force who was involved in the bust, Tati was a big get: a longtime mafioso suspected of ordering numerous hits. Torrez pleaded guilty and was sentenced to 13 years at Lompoc, a federal prison an hour north of Santa Barbara.

It was impossible for him to separate his two lives completely. Andres saw his father get arrested once. On another occasion, the narcotics cops who kept close tabs on Torrez pulled him over while he was running errands with Andres. When they noticed a white substance on the car’s dashboard, the police crowed, “We got you, Tati!” But it wasn’t cocaine; it was residue from a jelly donut that Andres had just finished eating.

Torrez told his kids that, although he couldn’t act as a role model for how to get up every morning and hold down a nine-to-five job, he could be an example of the awful things that would happen if they took the same path he had. “I’ve done enough time for everyone,” he said.

In 1995, the federal government filed an 81-page indictment against 22 alleged Mexican Mafia members and associates under the Racketeer Influenced and Corrupt Organizations (RICO) Act, the statute that designates penalties for offenses committed as part of an ongoing criminal enterprise. The FBI had flipped a high-ranking mafioso; he’d agreed to wear a wire, which netted damning evidence of murder, extortion, and kidnapping. Thirteen of those arrested were ultimately tried, and all but one were found guilty. At sentencing, prosecutors sought to cripple the gang by dispersing the convicted to various federal penitentiaries. Distance, they believed, would hamper communication and collusion. In fact, it helped the gang plant seeds across the entire country.

Over the next two decades, la Eme continued its vicious reign. There were murders on the streets of California, stabbings in attorney visiting rooms, and violent feuds with other prison gangs. Reportedly, in the early 1990s, the group considered assassinating California governor Pete Wilson over what it viewed as an anti-Latino proposition to bar undocumented immigrants from using certain public services. According to The Black Hand, a book by journalist Chris Blatchford, the California Highway Patrol received eight separate tips that Wilson might be in danger, including mentions of a $1 million hit by la Eme. The agency investigated the tips but found nothing. An assassination attempt never materialized.

In the early 1970s, a burst of brutality in California prisons attracted the attention of the FBI. There were 36 murders in 12 months, and officials believed that the Mexican Mafia was to blame for as many as 30. The FBI was also concerned that the gang might be infiltrating structures outside the correctional system. A special agent in San Francisco penned a classified memo in 1973 that described the gang (which “controls the major lines of narcotics into California prisons”) as having approximately 750 members. Based on information gleaned from confidential informants, the memo concluded that “the Mexican Mafia has become so sophisticated that it has put together an efficient intelligence organization, pools of sympathetic lawyers, has used revolutionary groups for its own ends, and has taken over respectable Mexican-American social action groups.” As members were paroled, they established sets across Southern California. In one instance, they allegedly infiltrated a nonprofit center for disadvantaged youth.

By 1961, the nascent group had perpetrated enough violence at the juvenile institution that its members were transferred to an adult penitentiary, San Quentin State Prison. San Quentin sat at the end of a small peninsula abutting the San Francisco Bay, not too far from Alcatraz. The Mexican Mafia quickly asserted its influence there, and by the end of the 1960s, the gang had extended its tentacles beyond San Quentin into every correctional facility in the state. Members deliberately caused enough problems at one prison—targeting guards, stabbing other prisoners, funneling in drugs from the outside—to get transferred to another facility, where they’d again use violence and intimidation to establish their authority.

Civil rights groups had chastised the prison for its extensive use of solitary confinement, but government officials heralded the ADX as exactly what the penal system needed. After touring the facility, Cheri Nolan, then a U.S. deputy assistant attorney general, told the press, “I’ve never seen anything like it as far as the technology and physical setup.” As far as violent incidents were concerned, the men and women who worked at ADX Florence were proud of keeping a clean record—until April 2005.

Jon learned that each general-population cell, constructed mostly from poured cement, contained a concrete-slab bed with a thin mattress, an unmovable stool, a writing surface, a toilet, and a sink. To avoid guards having to escort prisoners to a shower block, where they would encounter fellow inmates, the cells were equipped with timed showerheads. Each cell had a single thin window and two doors—an interior grate and a solid exterior—separated by a space called a sally port, which provided an extra layer of containment; an inmate couldn’t slide, say, a note or shank under his door for another man to grab. Meals were delivered directly to prisoners three times a day. There was no reason for a man to leave his cell, save for limited rec time.

The next facility designated for high-risk prisoners was a penitentiary in Marion, Illinois, a small town five hours south of Chicago. Then, on October 22, 1983, members of the Aryan Brotherhood, one of the country’s most powerful prison gangs, stabbed to death two correctional officers in separate attacks on the same day. The bloody incident at Marion prompted the head of the Federal Bureau of Prisons to advocate a new approach: a lockup built specifically to keep problem inmates in near total isolation. The result was ADX Florence. The $60 million, state-of-the-art facility opened in 1994.

That was by design. Once upon a time, Alcatraz was the only federal maximum-security prison. The storied facility in the San Francisco Bay began housing inmates in 1934 and operated for three decades, at which point someone crunched the numbers and realized that the expense of running the Rock, as it was called, was three times greater than the operating cost of any other prison in the country. It was pricey to stock it with supplies, for one thing, including the million gallons of fresh water that had to be shipped there every week. So the feds shuttered the prison in 1963.

After Jon graduated from college, he followed in his grandfather’s footsteps and joined a police force, starting out as a patrolman and working his way up to detective. He investigated robberies, kidnappings, and homicides. After a few years on the job, he started imagining what it would be like to work for the FBI. Jon liked the idea of operating with national jurisdiction and solving major crimes. He assumed, however, that he’d never make the cut to join the bureau, so for a while he didn’t try. Then one day some fellow detectives talked him into submitting an application, after which he’d have to take a written exam. To save himself the embarrassment of announcing that he’d failed, Jon decided not to tell his family what he was doing.

III.

Jon began his investigation by reviewing what the prison staff knew. As guards cleared the rec yard, one of them had noticed that an inmate’s shoes were spattered with blood. The prisoner’s name was Richard “Chuco” Santiago. He was a short man with a thick build and intricate tattoos, including several Aztec figures, covering his arms and chest. When guards arrived at his cell, they found Santiago stripped to his boxers and bent over his toilet, dunking his clothes and shoes in the water.

“What do you want?” Santiago asked as the officers entered the sally port. “I’m just washing some clothes.” The guards ordered him to stop. He looked right at them and kept going. Only when he was threatened with forceful extraction did he comply.

Santiago wasn’t a troublemaker. The guards considered him polite and respectful, and it was unusual for him to ignore an order. Still, there’s a common saying at the prison—no one winds up at ADX Florence by mistake—and Santiago was no exception. At 45, he’d amassed an extensive rap sheet that stretched all the way back to his teenage years: armed robbery, assault with a deadly weapon, felony possession of a firearm, narcotics violations, parole violations. When he committed the crime that put him away for life, he was already locked up. On the afternoon of January 25, 1989, he stabbed another inmate to death while working his shift in the kitchen at Lompoc. DNA testing linked Santiago to the crime, and his cell mate testified at the trial that, a few weeks before the murder, Santiago had asked what it would take to get into a prison gang. The cell mate also said that, the night before the killing, he’d overheard Santiago discussing a hit with a member of the Mexican Mafia. Santiago was found guilty in 1993 of the murder that, in all likelihood, had secured his place in la Eme.

After moving Santiago to a holding area, the ADX guards’ next step was to review the tapes from the rec yard’s cameras to figure out what they’d missed. The eerie, gruesome footage began at 8:15 a.m., six minutes before Guadian noticed Torrez on the ground. Torrez was doing toe touches near a camera in one corner of the yard. Santiago and another inmate, Silvestre “Chikali” Rivera, stood about ten feet away. Rivera swung his arms in a windmill motion, as if warming up for a workout. Santiago approached Torrez alone, and Torrez appeared to reach out to shake Santiago’s hand. Then Santiago darted at him and threw a punch. The blow pushed Torrez backward, directly underneath the camera. His position made it impossible for the lens to capture the attack.

The only other camera in the yard was in the far corner, which also made it difficult for officers Guadian and Aragon to spot what happened next: Rivera and Santiago punching and kicking Torrez in the ribs and head for two minutes straight. The attackers then took breaks, walking away from their victim. At one point, Santiago sipped from a water bottle. Then he went back and delivered several more blows. Torrez’s body jolted with the impact of each kick but was otherwise motionless. Four minutes after the final phase of the assault, guards arrived at the yard.

Later, when officers went to retrieve Rivera from his cell, he appeared to be shaking. The 47-year-old had never been charged with murder; he’d first gone to prison in 1979, when he was 21, for committing a string of bank robberies. He’d struggled with heroin addiction, and his prison file included write-ups for assaults on other inmates, peddling illegal drugs, and cooking a 25-gallon batch of contraband wine. Once, at another facility, he’d tried to escape by using a hacksaw to get out a window. He’d been transferred to the ADX from another lockup for beating and biting inmates and getting caught with heroin.

The day after the murder, while moving through a special housing unit for disciplined inmates, Rivera spoke to the guards escorting him. “I know you guys are mad at me for what I did,” he said, according to one of the officers.

The guards didn’t respond. Rivera kept talking.

“While I’m at rec, I heard this was the first at this facility,” he said. “Is that true?”

“What are you talking about?” an officer responded.

“What I did,” Rivera said. “I heard it made the news.”

When Jon watched the security footage, he wondered what there was to investigate. The case wasn’t a whodunit. This is ridiculous, he thought. It’s so obvious. Jon figured even the greenest of prosecutors could hit play on the tape and have a reasonable shot at extracting guilty pleas from the two inmates. And if the men didn’t admit what they’d done, surely it wouldn’t be that hard to convince a judge and jury to convict them.

“Boy,” Jon told me, “I didn’t know what I was talking about.”

Among the things he didn’t immediately comprehend were the legal peculiarities of the prisoners’ circumstances. Santiago was already serving life in prison; Rivera had another 15 years behind bars. In the grand scheme of the men’s incarcerated lives, a plea deal for, at a minimum, a few decades would mean very little. The government wanted to send a message to gangs: Stop killing behind bars. The question, then, was how to punish prisoners who’d all but reached the end of the line. One possible answer was the death penalty.

The Justice Department’s Capital Crimes Unit reviews federal cases that are eligible for death-penalty proceedings, and all first-degree murders are eligible. The death squad, as it’s known among defense lawyers, exists so that the same standard is applied to capital cases in Colorado as in, say, Georgia. Requesting permission to take someone’s life, however, calls for more than grainy video from a security camera. To begin with, it requires proving intent and premeditation. In the Torrez case, that would mean examining the inner workings of the Mexican Mafia.

Jon saw a thread that, once tugged, might help him unravel the backstory of the crime. Torrez and Santiago had been at ADX Florence since 2000 and had been housed in the same unit for almost a year; they’d been in rec yards together dozens of times and never seemed to be in conflict. Rivera, on the other hand, had arrived at the prison only a few weeks before the murder. The morning of the crime was only the second time he’d ever been outside for group rec. Jon wondered if Rivera had been the catalyst for the killing.

That question also piqued the interest of the prosecutor assigned to the case. Bob Mydans, a fit man in his fifties, with a square jaw and a full head of dark hair, was a longtime assistant U.S. attorney in Denver known for handling complex litigation. He’d helped bring down the city’s major mob family, the Smaldones, and prosecuted the so-called Cowboys, seven prison guards indicted for conspiring to deceive, threaten, and even torture inmates and hide the evidence.

In early 2007, Mydans invited Jon to his office on the 16th floor of a high-rise building with sweeping views of Denver’s downtown. Jon, who lived south of the city, didn’t make the trip to the capital often. It felt bureaucratic and stuffy. He preferred a slower pace of life and easy access to the mountains. He was relieved when he instantly connected with Mydans. They shared a deep love of the outdoors, and Mydans, 23 years Jon’s senior, boasted of exploring every continent except Antarctica. They talked about hikes in Rocky Mountain National Park that tourists too often skipped.

Then they began formulating a plan to tackle the ADX case. According to prison guards, a rumor was floating around that Santiago was a torpedo, slang for someone designated to carry out la Eme’s bloody business on the inside. If true, high-ranking mafiosi had decided to green-light Torrez, or mark him for death. Then they’d gotten word to Santiago, possibly through a messenger. One of the leaders of the Mexican Mafia, Adolf “Champ” Reynoso, was locked up at ADX Florence. Could he have called the shots? Or could the green light have come from a mafioso at another prison or one living on the outside?

Before Jon drove home, Mydans proposed setting up an office for the FBI agent next to his own. He wanted Jon to have the option of being just a shout away the deeper they dug into the case. “We both knew what we were getting into,” Jon told me.

The Mexican Mafia purportedly kept a secret list of approved hits. “Every now and then, a copy would surface,” Jon said, “and it was freakin’ 15 pages long.” The lists were almost certainly fake; the real one, if it existed, lived in the minds of the gang’s leadership.

If Torrez had ever been targeted for a hit, the FBI’s field office in Los Angeles might know. No place in the country boasted more experts on la Eme, and at least one analyst worked the beat full time. Jon and Mydans decided to pay them a visit.

When the two agents stepped off the plane onto a jet bridge at LAX in 2007, the sun was warm and bright. It felt invigorating. What they encountered at the FBI office did, too; the place was like a library stocked with every book they needed. “They had a ton of intel,” Jon said, ranging from historical documents about the gang to files on current members. “We wanted it all.” That was the strategy: collect as much information as possible and sort through it later.

Agents in L.A. shared the taxonomy of Mexican Mafia power players and a rundown of who was housed in which prisons. They also offered access to two pools of valuable sources. The first were behind bars: men associated with la Eme who had struck a deal agreeing to pass along information and rumors to the FBI. The second were gang defectors, who at great risk to themselves had provided information about la Eme to the government. They’d been placed in witness protection and were living under new identities in remote locations across the country.

Jon and Mydans decided to meet with countless sources in person. “It’s not like you’re going to get a subpoena and read through their email,” Jon said. He and Mydans flew all over the country, visiting dusty towns with a couple of stoplights and a Chili’s. Mydans seemed to relish the work. He was a traveler at heart. “Everywhere he went, it was going to be an adventure,” Jon said. Mydans loved to stop locals on the sidewalk and solicit restaurant recommendations. To him, eating ribs off a paper plate at a hole-in-the-wall barbecue joint was a form of enlightenment.

Among the people they met with were ex-mafiosi. Jon couldn’t tell me who the defectors were, where they were located, or the specific intelligence that they shared. Putting identifying information into the world risked the Mexican Mafia showing up on its former members’ doorsteps and killing them on the spot.

The trips produced several explanations of why la Eme might have green-lit Torrez, but one came up more than the others. Before his arrest in the 1999 RICO case, Torrez had been involved in the drug trade in Southern California. He’d used the Mexican Mafia’s muscle and threats of violence to collect taxes from dealers and junkies; they paid him for the right to sell and to use on the streets. But Torrez overstepped. He wanted taxes from another mafioso’s territory, so he’d had the man killed—a clear violation of two gang rules: You don’t interfere with another member’s business, and you don’t unilaterally decide to kill another mafioso.

That would mean Torrez was murdered in 2005 for something he’d done in the 1990s. Such a long delay isn’t unheard of. In the Mexican Mafia, it can take years for information about an offense to circulate, and even longer for leadership to sign off on a hit, given how diffuse and secretive the gang is—to say nothing of the fact that, in many instances, both shot callers and their targets are in lockup.

Jon and Mydans came to believe that Rivera was the messenger who’d arrived at ADX Florence with confirmation of the green light and communicated it to Santiago. During the investigation, Jon heard stories of the extraordinary lengths la Eme went to when it wanted that kind of information conveyed. The message didn’t always come directly from a high-ranking member. Maybe another inmate had told Rivera while riding with him in a transfer van or sitting with him in a holding cell. Or maybe word had been passed through a corrupt correctional officer or attorney.

Equally alarming were tales of how la Eme manipulated legal cases against its members and associates. The gang viewed discovery—the phase when lawyers share evidence in advance of a trial—as a fact-finding mission. It was an opportunity to identify defectors and snitches and to learn how the feds were gathering their intelligence. Armed with that information, the Mexican Mafia could figure out ways to clog the investigative process or order hits against cooperators. “They value life so little, it’d be nothing for them to go put a shank in somebody just so they could take it to trial and corner all these witnesses up,” Jon told me.

Jon watched the security footage of Torrez’s murder so many times that he lost count. Some days, when he and Mydans weren’t on the road, he would arrive for work, sit down at his desk, bring the video up on his computer, and hit play. He memorized the men’s movements and gestures. He looked for clues he might not have seen the previous dozen times he’d watched.

The morning of the murder, guards hadn’t taken Rivera out to the rec yard right away. It seemed to have been an honest clerical oversight. When Rivera hailed an officer to his cell and said that he should be outside, the guard checked prison records and realized that the inmate was right. Rivera was shackled and led to the yard. The whole process took about ten or 15 minutes. In the intervening time, as Jon saw on the security footage, Santiago appeared to wonder where Rivera was. At one point, he stood talking next to a small window in one of the walls facing the rec yard. Based on diagrams of the ADX, Jon could see that the window was in Rivera’s cell.

Because the footage had no accompanying audio, Jon decided to visit the ADX to discern what the inmates knew about the conversation. Maybe someone from a rival gang had seen something from his window or had heard a fragment of a rumor about what was said through a drainpipe, which carried voices between cells. Jon approached the prison’s in-house law enforcement, Special Investigative Services, for help.

“Do you guys have an interview room?” he asked.

“Yeah,” one investigator said. “But you can’t use it.”

No one wanted to be seen, willingly or not, talking to an FBI agent. It could mark him as a traitor.

Guards had to be crafty. One tactic, later discussed in court proceedings, was to pull an inmate from his cell under the pretense of a doctor visit or a lawyer call, then escort him to an out-of-the-way area where Jon waited on the other side of a thick pane of glass. Still, when prisoners saw or heard that someone was being moved through the block, they got curious. “Hey guard, why’s this guy getting out?” one would yell from his cell. If the answer was “dentist appointment,” the skeptical retort was, “I didn’t know he had teeth problems.”

Jon was nervous about the interviews. He mostly met with gangsters; the big-name prisoners, terrorists like the Unabomber, were segregated in special units, disconnected from where the Torrez murder had happened. Jon sat across from men with hard-bitten countenances. Lives of violence and incarceration had left them tattooed, scarred, and bitter. Some had been locked up by the FBI, and when Jon flashed his badge, they turned hostile and demanded to be taken back to their cells. Others, though, seemed desperate to talk. Not about the murder—no one, it turned out, had anything pertinent to say about that. They just wanted to shoot the shit. The men had stumbled into a disruption to the monotony of their daily lives and wanted to stay in it as long as they could.

Though Jon came away from the interviews with very little, the ADX guards shared an important tidbit. Just before he was killed, Torrez had used the yard’s intercom system, which allows inmates to ask guards questions. He’d asked where Rivera was. “It’s crazy,” Jon told me. “He’s inviting his killer to come outside. It’s like [the gang] got word to him that Rivera’s got something he wants to share that’s really important. Then Rivera shows up and it’s, ‘Yeah, by the way, you’re green-lit.’”

By early 2010, Jon and Mydans were confident that they had the evidence they needed to support their green-light theory. Mydans filed a straightforward, two-count indictment at the federal courthouse in Denver. It alleged that Santiago and Rivera had “willfully, deliberately, maliciously and under premeditation and malice aforethought” killed Torrez. It kept details about the hit, like who might have ordered it, to a minimum. Presumably, Mydans wanted to hold that knowledge close until trial.

Court was still a long way off. There would be standard pretrial motions and maneuverings. More important, the Capital Crimes Unit had to decide if it wanted Mydans to pursue the death penalty. He and Jon waited a year before they heard from the unit.

In March 2011, Mydans announced that he would seek the death penalty against Santiago but not Rivera. The reason why was tied up, at least in part, with a deft move by Rivera’s defense attorney, David Lane. A prominent Denver lawyer whose name was on a short list of people approved to act as court-appointed counsel in capital cases, Lane had taken Rivera’s case in 2010. Like Jon, when he first watched the security footage, he felt uneasy. It reminded him of an old newspaper cartoon in which a lawyer sits in a jail cell talking with his client. In Lane’s recollection, the caption said something to the effect of, “OK, the crime is on videotape. You’re plunging the knife in 52 times. Then you get in your car, run over the guy. It was in Times Square, and there are 10,000 eyewitnesses. Your fingerprints are on the knife, and your DNA is all over the body. Now, here’s my plan.”

Lane decided that his first duty was to save his client from the death penalty. On that front, he saw an opening. When he learned about the unsolicited comments Rivera had made to a pair of guards the day after the murder, seemingly admitting to the crime, Lane noted two relevant facts: First, although he’d spent much of his life in America, Rivera was a Mexican citizen. According to the Vienna Convention, an international treaty, citizens of one country arrested in another must immediately be appraised of their right to speak to counsel. The second fact was that no one had advised Rivera of that right. Testimony about Rivera’s comments, Lane believed, shouldn’t be admissible.

Arguing that the government had violated the Vienna Convention wasn’t an ironclad legal tactic—among other problems, the Senate has never ratified the treaty—but it was a canny diplomatic move. The Mexican ambassador to the United States agreed to write a letter to then attorney general Eric Holder and secretary of state Hillary Clinton. “The Government of Mexico has no record of any consular notification ever being provided in Mr. Rivera’s case,” it stated.

Two months after the letter was delivered to officials in Washington, Mydans announced his intent in the case. Rivera sidestepping a death-penalty prosecution meant that he and Santiago would be tried separately. Rivera’s trial would come first. Before it could begin, though, tragedy struck.