Harper’s Magazine and Scott Horton were not supposed to win the National Magazine Award for Reporting this year. Of the five finalists in the category, there were three real contenders, and most people working in the ever-shrinking category of serious magazine journalism were sure the award would go to Rolling Stone for the article by Michael Hastings that led to the downfall of Gen. Stanley McChrystal or The New Yorker for Jane Mayer’s profile of the billionaire Koch brothers.

But Harper’s beat out the two big names, scoring a major upset with Horton’s piece about three detainees at Guantánamo Bay who died in 2006. The government said the men had hung themselves in an effort to bring on a public relations crisis that might force the U.S. to close the prison. But Horton laid out a case that they had in fact been killed—whether deliberately or inadvertently—during a torture session.

In fact, Horton’s story, which the judges for the award—administered by the American Society of Magazine Editors (ASME) and regarded as the Pulitzer for magazines—found so compelling, was actually a well-shopped one, familiar to some of the most experienced investigative journalists in the business. These included The New Yorker’s Seymour Hersh as well as teams from CBS News’ 60 Minutes and ABC News’ Brian Ross Investigative Unit that had looked into the alleged killings and the accounts provided by the men who became Horton’s key sources, and found more flight of fancy than fact. (Horton acknowledges in his story that his source had been in contact with ABC News.)

Jim Miklaszewski, NBC News’ chief Pentagon correspondent, was another of those journalists. He worked on the story off and on for four months, during which time he reviewed “thousands of pages” of documents, interviewed Horton’s main source, and “talked to at least a dozen people.”

“Ultimately I just didn’t find the story credible, quite frankly,” Miklaszewski says. “I devoted a lot of time to it, and my conclusion was that it just didn’t seem possible that that many people could have been involved in a conspiracy and to have [the killings] remain secret. It stretched all credulity, I thought.”

Hersh confirmed to Adweek that he had dug into the story and dropped it too. A New York Times reporter was also approached by the parties who’d been pushing the allegations of homicide and cover-up at Guantánamo, a person close to the situation says.

Only after the big guys passed was the story shopped to Horton. He won for reporting, but in fact the story fell right into his lap, factual flaws and all.

“We couldn’t really believe it when the piece came out,” one of the reporters who looked into the story says. “I can’t believe Harper’s, I really can’t.”

A year before Horton’s article appeared, the man who would become his main source, Sgt. Joe Hickman, contacted Mark Denbeaux, a lawyer and professor at Seton Hall University School of Law in New Jersey, who has represented detainees at Guantánamo. Denbeaux and his students had put together a paper raising questions about the deaths and posted it online, and Hickman—who’d been on duty as a guard at Guantánamo the night the men died—had read it. He had a story about those deaths to tell. So he called Denbeaux and, Horton writes, told the lawyer, “I know some things you don’t.”

Hickman and Denbeaux met in person two days after the phone call. Then, together with Denbeaux’s son, Josh, who’s also a lawyer and who currently represents Hickman, the three men started shopping Hickman’s story around. In February 2009, the Denbeauxes went to the Justice Department, and to Congress, though according to Horton, they broke off their contact with Congress at the DOJ’s request. Then, that spring, they approached 60 Minutes. A team from that show spent at least a month investigating Hickman’s account. When 60 Minutes opted not to go any further, the Denbeauxes went to ABC News, which spent a considerable amount of time on the story before it, too, decided to drop it.

Both of those news teams spoke with the sources from Guantánamo who are named in Horton’s article. Both determined that their accounts were unconvincing.

What made Hickman and the other sources seem unreliable to the networks? In part it had to do with who and where they were at the detention center at U.S. Naval Station Guantánamo Bay (which includes Camp Delta, where the prisoners who died were housed). Officially, all U.S. military personnel fall under one umbrella, Joint Task Force Guantánamo. But when it comes to actually guarding the prisoners held in Camp Delta, the various branches have very different responsibilities.

The people on the inside of the camp, the ones who actually guard the detainees up close, are Navy. The guards who patrol the exterior of the camp are Army. Hickman and Horton’s three additional main sources were Army. The dozens of witnesses who informed the government’s official report on that night were predominantly Navy.

In other words: Horton’s main sources were perimeter guards, distant from the prisoners.

This was a major sticking point for reporters investigating the deaths.

“While Joe seemed like a sincere, nice guy, he just wasn’t in a position to see what he says he saw,” says one of the major news organization reporters who also looked into the story. “With Hickman, literally we had tons of aerial shots of this place, and said, ‘Where were you exactly?’ ‘At what time?’ And we compared that with some of the official reports of the suicide, and it didn’t match up.”

Adweek made multiple attempts to reach Hickman for comment—through his email, and through the team of representatives he’s assembled: literary agent Stu Miller, who says he has represented screenwriting talent like Aaron Sorkin in the past, and through his publicist, Glenn Selig, whose big client has been former Illinois Gov. Rod Blagojevich. All were unsuccessful.

This is, in brief, the official version of what happened the night of June 9, 2006, as laid out in thousands of pages from the government’s investigation, which were released under a Freedom of Information Act lawsuit.

A group of detainees at Guantánamo, angry and frustrated about their indefinite captivity and the conditions of it, wanted to make a public relations splash, something that might force the U.S. to close the prison. And so they turned to arguably the most powerful weapon in their limited arsenal: suicide.

Three detainees—Ali Abdullah Ahmed Naser al-Salami, Mana Shaman Allabard al-Tabi, and Yasser Talal al-Zahrani—were the ones who carried out the mission. They did so with the knowledge of at least some of their fellow prisoners. That’s why the men in nearby cells kept quiet, even though prisoners, believing suicide un-Islamic, generally alerted guards to suicide attempts. And that’s also why, at around 8:30 p.m., just a couple hours before the three men hung themselves, a group of prisoners joined together from their cells to sing a Taliban death song.

Salami, Tabi, and Zahrani hung up blankets and propped up mattresses in their cells to make looking in more difficult, but not so difficult as to violate the ad hoc rules of the cell block and attract guards’ attention. When the lights on one side of the tier were turned off at 10 p.m., they went to work. They used some of the “comfort items”—an extra blanket, an extra towel, extra clothes, and so on—they’d been issued to form dummies and fool the guards into believing they were asleep. They made other items into cloth masks with mouthpieces that would prevent them from crying out, or at least muffle any noise. Then each of the men tied a noose to their respective cell’s wall and hung themselves. They hung there undiscovered—maybe because the guards were lax, maybe because the guards had been hamstrung by commanding officers who wanted to keep the peace, probably both—for more than two hours, until they were discovered, one by one, starting sometime a little after 12:30 a.m.

By then, Salami, Tabi, and Zahrani were clearly past any hope of rescue—their bodies had already begun to go into rigor mortis—but they were taken to the nearby clinic anyway, and because there was no doctor there to declare the men dead, medical personnel worked frantically on them, even transporting Zahrani to the base hospital. Around 1:15 a.m., Salami and Tabi were pronounced dead. Thirty-five minutes later, Zahrani was too.

And this, in brief, is Horton’s version of what happened:

Hickman began his 12-hour shift as sergeant of the guard for the exterior security force at 6 p.m. on June 9, 2006. He began that shift from a perch at Tower 1, which stood above the main entrance to Camp Delta.

Not long after he began working, Hickman saw what he and other soldiers referred to as the “paddy wagon,” a white van typically used to transport prisoners “to medical facilities and to meetings with their lawyers.” In this case, Hickman saw it parked near Camp 1, the section of Camp Delta where the three detainees lived, and watched two Navy guards take a prisoner from Camp 1 and put him in the van. From there, he saw the van take an uncommon route—where normally it would make a right, it made a left, heading toward a checkpoint called ACP Roosevelt. Past that checkpoint, there were only two places it could go: to the beach or to a secret site, which a friend of Hickman’s called “Camp No,” as in, “No, it doesn’t exist.” Soldiers at the detention center speculated about what this “Camp No” really was; one of their theories was that it was used by the CIA.

Hickman had seen the van take this route before, and he was curious about it. So when the vehicle returned about 20 minutes later, and the guards picked up another prisoner, then headed off again in the direction of “Camp No,” he was really interested. Twenty minutes later, the van was back again. Now Hickman had to see where it was going, so he left Tower 1 and drove to ACP Roosevelt, where he watched the paddy wagon drive by and make another turn toward “Camp No.” All this happened before 8 p.m.

Hickman didn’t see much else going on until about 11:30 p.m., when he watched the paddy wagon return again. This time, though, it headed for the medical clinic where it looked like it was dropping something off.

About 45 minutes later, Camp Delta was suddenly abuzz; floodlights on, personnel rushing in. Hickman headed for the clinic, which was the focus of this activity. Once there, he was told three dead prisoners—one of them severely bruised—had been delivered. They had died, a medical corpsman told Hickman, because rags had been stuffed down their throats. Specialist Tony Davila, a friend of Hickman’s, heard the same thing from Navy guards.

Hickman asked his guards what they had seen. Specialists Christopher Penvose and David Caroll both told him they hadn’t seen any detainees taken to the clinic.

That morning the story spread throughout the personnel at the detention facility: Three prisoners had killed themselves by swallowing rags. And then Col. Michael Bumgarner, the warden of the detention facility, held a meeting with at least 50 of the guards. “You all know” the prisoners had killed themselves by swallowing rags, he said, but the media would report instead that they’d hung themselves, and they shouldn’t tell anyone anything different. (In an interview with Adweek, Bumgarner strongly denied giving the speech Horton reports.)

Horton also questioned the autopsies that the military conducted on the three detainees and, in an effort to undermine the official report, offered details from independent autopsies that the detainees’ families had commissioned once the bodies were returned to them. But he left out one key detail. At least one of the independent autopsies ended with the conclusion that hanging was, in fact, the most likely cause of death.

Horton notes, correctly, that the two pathologists who led those independent autopsies (a single pathologist was responsible for examining both Tabi and Zahrani) were concerned that the U.S. government had, because its investigation was still ongoing, not sent parts of the men’s throats that would be key to making a definitive determination of the cause of death.

Horton also spends a paragraph detailing the concerns that Swiss pathologist Patrice Mangin, who led the team that conducted the independent autopsy on Salami, had after concluding his report: injuries in the “oral region” that were too severe to be caused by resuscitation efforts and marks on the prisoner’s neck that were not related to hanging.

Yet Horton left out a key conclusion of Mangin’s report. “The cause of death is most likely the consequence of mechanical asphyxia by violence exercised against the neck as part of a hanging, without being able to formally exclude a different mechanism,” said the report, which was written in French. Mangin reiterated this point in a press conference.

Asked about this omission, Horton emailed: “Mangin’s major point was that without things that were withheld (the original autopsy report backup, the throat matter, etc.), it was not possible to reach a definitive conclusion. [Mangin] stressed that at the time he was trying to coax the Americans to cooperate, but that proved fruitless. . .Earlier drafts of the piece contained much more detailed discussion of the autopsies, including much more from Mangin and comments from Michael Baden, who independently reviewed much of the file, but much of this was taken out as a result of editorial decisions to get the piece down to roughly 8,000 words.”

This elision is hardly the only problem with Horton’s story. Remember the white van from Hickman’s account? The guard saw the van make the left turn where, in Horton’s words, “In that direction, past the perimeter checkpoint known as ACP Roosevelt, there were only two destinations. One was a beach where soldiers went to swim. The other was Camp No.”

But that’s wrong. And had the National Magazine Award judges done a little Googling, they would have known it, too.

Slate’s Jack Shafer—who, along with First Things’ Joe Carter, was one of the sharpest critics of the Harper’s story when it first appeared—reported this back in February 2010. Shafer printed an email he received from Dwight Sullivan, who’d been chief defense counsel in the Office of Military Commissions, in which Sullivan wrote, “After driving from the detention camps and passing the checkpoint, every facility on the Naval Station was a potential destination. This includes facilities to which detainees were sometimes transported, including the main hospital and the military commission building.”

Bumgarner confirms this. The checkpoint, he told Adweek, “is the main entry-exit point for Camp Delta.”

Horton told Adweek, “It’s true, of course, that when you drive out and you get on roads, you could take roads almost anywhere, there were connections that went on, but everyone I spoke with said ‘No, you would not have driven to that part of the base using that road, there were other roads that would have taken you there much more directly.’”

That’s not the only problem with the story about the white van. Hickman only saw three unidentified prisoners; he has no way of knowing whether the men he saw were the ones who died later that night. And in his telling, the men he saw would have all been taken to Camp No between 6 p.m. and 8 p.m. But multiple witnesses told government investigators they saw all three of those men in their cells and alive during that time, and even later, until at least 9:30 p.m.

“It’s important to understand that it’s very common that we would have towers calling in to the op center reporting something as if something really crazy’s going on, and it was just normal activity,” Bumgarner says. “It was just their lack of understanding because they didn’t really know what’s going on in that world.”

Horton’s piece had all the elements of a great story: a gripping narrative, a whistle-blower, an explosive expose, and a murder mystery—not to mention an admirable aim: to speak truth to power. But its approach was less methodical reporting and more conspiracy building, favoring the evidence that supports the conspiracy view and minimizing the evidence that does not.

That approach then received the National Magazine Award seal of approval. Indeed, the award citation calls the story “scrupulously fair.”

ASME refused to identify the editors who acted as the judges in the category.