When the Twiggs brothers got to the Grand Canyon, on May 12, Willard called his girlfriend, a married woman in Louisiana, on Travis’s mobile phone. She had to see the canyon someday, he said. “It will make the hair on your arms stand up.” A few minutes later, driving east along the South Rim past a spot called Twin Overlooks, Travis took a sharp left and drove his Toyota Corolla straight towards the 5,000ft drop. The Corolla jumped over the kerb, but did not take the plunge. It got caught in a small fir tree clinging just below the rim.

Travis and Willard Twiggs were not in trouble with the law. Willard, 38, was a former maritime-logistics specialist in New Orleans. He had been working in construction, intermittently, since Hurricane Katrina. Travis, 36, was a Marine Corps staff sergeant, a decorated combat veteran with one tour of duty in Afghanistan and four tours in Iraq. In January 2008 he had created a minor stir by writing an article about his struggle with post-traumatic stress disorder (PTSD) in the Marine Corps Gazette.

Twiggs emphasised his recovery; he soon found himself working with a new unit, the Wounded Warrior Regiment, spreading the word about the treatment and prevention of PTSD. In late April, he met President Bush at the White House. Rather than shake the president’s hand, Twiggs bear-hugged him, proclaiming: “Sir, I’ve served over there many times — and I would serve for you any time.”

Three weeks later, he tried to drive into the Grand Canyon. Witnesses said the brothers behaved oddly after the crash. They tried to reverse the Toyota out of the tree branches but could gain no traction. They did not want anyone to call for help. One seemed interested only in finding his cigarettes. They put on backpacks, said they were going to continue with their plans, and set off on foot before park rangers arrived. More likely, they went across the road and waited in the scrubby conifer forest while the rangers cleared the wreck.

An hour after the rangers left, while dusk was falling, the Twiggs brothers approached two tourists in a rental car. A .38 revolver was displayed. The Twiggs brothers got into the car and drove away. Now they were in trouble with the law. From their car, rangers had already deduced who they were. They had called Kellee Twiggs, Travis’s wife, in Virginia. She had missed a call from her husband earlier that afternoon. He and Will had disappeared a few days before. She was stunned to hear that they were in Arizona. She explained about the PTSD and said that Travis had been “out of his mind” the last time she saw him.

He was a highly trained marine — a martial-arts instructor, weapons expert and skilled combat tracker. “I’m very scared,” she said.

“I don’t want anything bad to happen to him or your people.” Anyone who approached him should use his nickname, Tebeaux; it might help him understand that he was in America and that they were not the enemy. She added that her husband’s combat flashbacks were worse if he had been drinking. In the towed car, the rangers found beer cans and an empty bottle of Jägermeister.

The bulletins that went out over the wires gave Travis and Will a “violent criminal history”, although neither had any before the carjacking. The Twiggs brothers might be bent on committing “suicide by cop”, said one alert. The two men were certainly leaving the world as they had known it. The lingering, punishing question is why. Travis, who had two young daughters whom he doted on, might have believed that he was back in Iraq. Will’s thinking was more opaque. They drove into the night. Two days later, they were dead.

“You cut him and he bled green,” said Kellee Twiggs, flinging shrimp into a pot. She meant that her late husband’s devotion to the Marine Corps was total. A portrait of Twiggs in uniform hung near the front door of her house, a few miles south of Quantico in Virginia. A box of his medals and ribbons stood near the dining-room table. His ashes sat in a brass case decorated with the Marine Corps eagle, globe and anchor.

Kellee and Travis met when she was five and he was eight, and they lived on the same block in New Orleans. Kellee is a trim, lively woman with short, hennaed hair and a lush Louisiana accent. Tebeaux is Cajun; it means “handsome little man”.

Kellee and Travis both came from large families. Travis was a middle brother. “Will was the smart one,” Kellee said. “He read the paper. Tebeaux was the mischievous one.” Will and Travis idolised an uncle, Ricky Taylor, who had been an infantryman in Vietnam. Another uncle, Dave Twiggs, had been badly wounded there.

Travis enlisted in 1993; they married in 1999. Twiggs tried civilian life for a year, working for his father’s shipping agency in New Orleans, but he craved more structure. His father, Douglas, said: “He needed regimentation.” Kellee said: “Tebeaux liked being in the woods, teaching boys things, how to survive. We got back in the marines in January 2001.”

Travis had acquired a new nickname in the military. After an extra-long duty shift at Guantanamo Bay, he had fallen into a heavy sleep and a general had stuck a sign on him: “Here Lies the Mighty War Pig.” The Twiggses’ house became a surrogate home for many of Travis’s men. “He was like their dad,” Kellee said. “They came to him at 4am with their problems — financial, marital — and he always got up.” Her right foot and ankle carry a huge tattoo, “Travis”, in gothic script. “He had my name all over him,” she said. “On the top of his left foot. On dog tags off his shoulder. ‘Kellee’, ‘Ireland’. He hadn’t got ‘America’ put on there yet.” On his right forearm, she said, Travis had “Gladiator”; on his left, “Spartan”. “My husband was my everything,” she said. “He was my hero.”

Kellee flicked a cigarette butt off the porch. “You got your daddy’s catfish mouth,” she told her daughter America. “See that?” She pointed to a photograph of Travis scowling; the resemblance was strong. “Me and Ireland [their older daughter] used to tell him, ‘You’re home now, you can smile. You can stop being a badass,’ ” Kellee said.

Douglas Twiggs says: “He’d tell his marines when they came to his house, ‘I’m Tebeaux today, but on Monday I’ll be Sergeant Twiggs.’ ”And for years Travis did manage, it seems, to leave War Pig at the front door. But after each overseas deployment the transition to family life grew more difficult. “I was more irritable, paranoid for no reason, unable to sleep,” he wrote.

He was not being forced to return to Iraq — he was volunteering. The moment that a new deployment was in sight, he wrote: “My symptoms went away. After all, I was going back to the fight, back to shared adversity, where the tempo is high and our adrenaline pulses through our veins like hot blood.” He didn’t talk much, at home, about what he did “in theatre”. He was frustrated by the press coverage of the war. “All they showed were the bad things,” Kellee said. “Then, after his third tour, we’d be watching the news and Tebeaux would start crying and shouting, ‘What the f*** am I fighting for?’ He got so twitchy, it became impossible to cuddle him. He loved movies, but he couldn’t sit still to watch one. You wanted to keep him busy, keep him talking about things so he wouldn’t start talking about other things. He’d hear a car coming up our gravel road and he’d just hit the floor, bam, because the tyres crunching sounded like machinegun fire. Or he’d sit upstairs and watch for lights, because that’s what he used to do in Iraq. I’d call his name, get him back to bed, put him in a bear hug and rock him. Then he’d sleep. But as soon as I moved he’d wake up.”

Travis started drinking heavily and having trouble concentrating. “His therapy was to cut the grass with his iPod on,” Kellee told me. “He did that a lot.” It was dark now, with a full moon rising. Kellee hadn’t touched her food. “He volunteered,” she said. “We volunteered. He was f***ing awesome, and he kicked ass because he loved his country. And when he got sick, got saddened, his government, his Marine Corps, let him down.” She started to cry.

PTSD has been around for as long as war has. Although Twiggs used the word “paranoid” to describe his mood at home, the more accurate term, used by PTSD researchers, might be “hypervigilance” — a normal adaptive strategy for surviving combat, except that the “on” switch is not easily turned off. Dr Jonathan Shay, a PTSD specialist, says the condition is best understood as a psychic wound that can be crippling, even fatal. A recent study estimated that 300,000 veterans of the Iraq and Afghanistan conflicts — nearly 20% of those who have served — are suffering from PTSD or severe depression. In Britain, more than 2,000 soldiers returning from Iraq have been officially diagnosed with PTSD, and that’s the tip of the iceberg. The charity Combat Stress has seen a 53% increase in new referrals over the past three years, and is already treating more than 200 Iraq veterans. In America only half of those afflicted seek treatment. Suicides are on the increase. The Wounded Warrior Regiment, created in 2007, marks a step towards longer-term institutional responsibility for casualties, both physical and mental. “Used to be we met them at the hospital door, shook their hand, gave them a discharge and said goodbye,” Colonel Greg Boyle, the regiment’s commander, told me. “Now it’s marine for life.” It was Boyle who sent Travis Twiggs to the White House. “Nice guy. I liked him.”

Travis Twiggs didn’t announce his PTSD at first. When he returned from Iraq in 2006, after his third tour there, he was transferred to a job at the Warfighting Lab evaluating new weapons systems. But without his beloved platoon Kellee said, Travis was bereft: “He felt like he wasn’t in the marines any more.” At his office job, his PTSD became impossible to ignore. Soon he was on the antidepressants Zoloft and trazodone, and self-medicating with alcohol.

Twiggs told Kellee that he couldn’t stand to look in a mirror. He was racked with guilt, in particular over the deaths of two young lance corporals in his platoon. The only thing that helped was returning to Iraq. He went, in late 2006, on a weapons-testing mission, and, once again, his symptoms vanished.

But once he was home, in January 2007, “he went batshit”, Kellee said. His PTSD — anger, sadness, drinking, flashbacks — took a toll on their marriage. Travis soon found himself in a locked ward at Bethesda Naval Hospital. “I was not exactly a model patient,” he wrote in his article. “I was experiencing psychosis where I would fight my way through the hallways and clear rooms as if I were back in theatre. The hospital police would have to be called in.”

Later, at a veterans’ hospital in West Virginia, he saw several doctors, “and it seemed that each one had a different medicine”. Kellee recalls him taking as many as 19 different medications in a day, which turned her husband into “a zombie”. He blamed his visual and aural hallucinations on being overmedicated. “On any given day I was sad, mad or depressed. I slept covered in sweat every night and constantly shook uncontrollably.” This was raw, vivid stuff for the Marine Corps Gazette.

Twiggs went on to describe his recovery and wrote: “I am back doing what I do best — training marines and sailors.” He offered advice to policymakers and PTSD sufferers, and included his e-mail address in case anyone in trouble wanted to contact him. His PTSD was “not completely gone”, he wrote, but “life with my family is wonderful again”. Twiggs became the Wounded Warrior Regiment’s PTSD poster-child. His symptoms, however, returned. He became impossible to live with. He was sent back to the hospital and, once again, Kellee thinks, overmedicated.

The experience that continued to cut Travis Twiggs most deeply was the loss of Jared Kremm and Robert Eckfield Jr, the young lance corporals in his platoon. They were killed at Saqlawiyah on October 27, 2005. The platoon’s firebase was an old Ba’ath party hotel near a main supply route to Jordan and Syria. The hotel compound was taking daily rocket and mortar attacks from Al-Qaeda in Iraq and from the Black Flags Brigades, a Sunni insurgent group. Twiggs was leading foot patrols through villages and along the banks of the Euphrates, searching for insurgents and for weapons caches. He was in his element.

Portable toilets had been set out in tents in the compound. These outhouses were vulnerable. His unit had been at Saqlawiyah for a month when Kremm and Eckfield took a direct mortar hit in the toilet tents. Twiggs was one of the first on the scene. Kremm had been hit in the face; Twiggs watched him die. Eckfield was alive but had severe head wounds. Eckfield was transported to a hospital near Falluja and died that night. Kremm, 25, from Long Island, had been a high-school football star. Eckfield was 23, from Ohio. Twiggs had trained them both and they had been regulars at his and Kellee’s house.

Christopher Lowman, one of Twiggs’s closest friends who served alongside him, told me: “When you train these boys, you tell them every day, ‘You do exactly what I tell you, and I will get you home.’ ” Mike Tucker, a writer and former marine, talked to Twiggs the night that Kremm and Eckfield died, and later said: “Something broke in Travis… That night, he told me, ‘I feel responsible for their deaths.’ ”

Travis’s family remained largely unaware of his struggles. His brother Will was an exception. In a journal, Will wrote: “My loyalty has unequivocally been to Tebeaux. I hope that God doesn’t take him away from me too.”

“Will thought of Tebeaux as a hero,” Kellee said. “Everybody was crazy about Will except Will,” Nancy Twiggs said. She is Will and Travis’s stepmother. She and Douglas raised them both, for the most part, in Ama, Louisiana, 20 miles upriver from New Orleans. They still live there, in a one-storey brick house. Nancy put on a video of Will, 11 years old, competing in a spelling competition. He wins; Travis, aged nine, rushes onto the stage and hugs his brother.

Nancy and Douglas Twiggs are heartbroken. Will, they say, was a devoted older brother. Will joined the navy after high school. In a snapshot taken aboard a ship in San Francisco, he looks, in navy whites, very young and frail, like a bird that has left the nest too soon. The physical contrast with Travis, 6in shorter but musclebound, is stark. Will did not last long in the navy. He went to work for a ship-chartering company in New Orleans. When his Uncle Ricky, the Vietnam-war infantryman, died, Will was inconsolable.

This loss intensified his fear of losing Tebeaux. “He was so proud of him,” said Douglas.

“We all were,” Nancy said. “Tebeaux made a better American out of me. He really believed in this country. I remember watching the first airstrikes on Afghanistan on television.

I thought, There’s Tebeaux. He’s in there, and he’s going to catch Osama Bin Laden. I truly believed that he would find him.”

Whenever Travis was at home, he and Will would try to rendezvous at Nascar races around the south. Both men idolised Dale Earnhardt Sr. Earnhardt was killed at the Daytona 500 in February 2001; the Twiggs brothers embarked together on an epic bender of mourning.

Will was jealous, Kellee thought, of Travis’s devotion to her and their children. “He could not appreciate that Tebeaux had found the love of his life, and had kids that let him love even more, and that none of it meant he couldn’t still love his brother,” Douglas said.

Will’s own love life was tormented. He seemed drawn to troubled women, usually older, often with drug habits. “They always seemed to have kids and work in bars,” a friend of Will’s told me. “Drama, drama and more drama.”

Will was distraught after one boy attempted suicide by slitting his wrists after Will left his mother. With his last girlfriend, Will convinced himself that her husband was after him, and started sleeping with a pistol and a knife under his pillow. Will had his own problems with drugs and alcohol.

He left his job with a German shipping company for one selling marine-radar systems. He earned a good salary, but became increasingly withdrawn. He quit the job just before Katrina. Then came intermittent construction jobs. He lost weight and let his hair grow long. “I started calling him Will o’ the Wisp,” Douglas said. “It was like watching one of those Japanese planes you used to see in those old black-and-white movies, shot down and spiralling towards the ground.”

A silence followed. It had been nine weeks since their sons’ deaths. “Neither would ever have done it alone,” Nancy said. “We sit out on the patio just about every night and try to figure out what went wrong,” Douglas said. “I almost feel like it’s getting worse,” Nancy said. “It’s like a big wave in the surf that knocks you sideways and holds you down, no matter how you fight it.”

After Travis was again released from Bethesda, in April, he and Kellee tried to regroup. “He had bad thoughts,” Kellee said. “I had bad thoughts. But I told him, ‘We’re badasses. We’re awesome. We’re killer.’ And we agreed, we’re in it together.” Travis had moved out of the house, into the barracks at Quantico, but he and Kellee tried to do things that would help them feel like a family. They took the girls to Washington, DC for a weekend.

Travis was at odds, however, with his colleagues at the Warfighting Lab. He believed that he had received a promotion, to gunnery sergeant, from the Wounded Warrior Regiment. But he was still officially under the command of the Warfighting Lab, and his recent performance there was not thought to merit promotion. Twiggs took the dispute as a rejection, a personal humiliation. He also wanted to go to Louisiana, where one of his grandmothers was dying, but his commanders considered him too unstable to travel alone. Twiggs saw more humiliation. He could not show up at his grandmother’s accompanied by a guard.

He and Kellee planned another family weekend, but Travis didn’t show up. Kellee was furious. When he finally arrived, on Sunday evening, he was drunk. She wouldn’t let him in the house, or allow him to see the girls. Instead, they sat together on the front porch and talked for half an hour. Her regrets from that night are ferocious. “If I had just brought him inside,” she said, “just taken him upstairs and made love to him, or tried to. Just told him it would be okay.” She never saw him again.

He drove on to Louisiana, on unauthorised leave, in their blue Toyota, with America’s car seat still in the back. He met up with Will, and the pair went to see their grandmother and their parents. They, too, are plagued with regrets. “I told him, ‘Tebeaux, you’re really not acting like my son,’ ” Douglas said. “If I’d known anything about PTSD, I never would have said that.”

Nancy recalled a letter Travis had sent from Iraq to be read at his younger sister’s wedding. “It said, ‘You may not be able to see me, but I’m there.’ I thought of that when we saw him so messed up. We could see him, but he wasn’t there. It just wasn’t him.” Douglas said: “None of us had ever seen him like that. It was like he was in a trance. He didn’t sound like himself. He was flatlining, like he had no personality. He said, ‘Dad, I think I’m very sick.’ ”

Travis and Will borrowed money from Kellee’s mother, Debbie Graham, and from one of Will’s ex-girlfriends. By Friday, May 9, the brothers had left Louisiana. They told nobody where they were going. Near Killeen, Texas, they dropped in on their uncle Dave Twiggs, arriving in a rainstorm on the night of May 9. Dave was disturbed by his nephews’ appearance and sat up late with them. He advised Travis to turn himself in at Fort Hood, just up the road, in the morning. Dave loaned them $100. Travis and Will left in the morning, but they did not stop at Fort Hood.

In El Paso, they dropped in on Kim Barron, an old friend of Will’s. She, too, was disturbed, particularly by Will’s appearance: gaunt, quiet, stricken. He hugged her and told her he loved her. Travis, by contrast, seemed fine.

They stayed for only half an hour. Travis said that he had to get back east.

When Kellee got the Toyota back, months later, Pink Floyd’s The Wall was in the CD player. “Mother will they put me in the firing line? / Mother am I really dying?... I don’t need no arms around me / And I don’t need no drugs to calm me... Would you like to call the cops? / Do you think it’s time I stopped?... Goodbye cruel world / I’m leaving you today.”

Travis, while he was hospitalised, made paintings — lurid depictions of his nightmares. Stained shows a marine holding an eyeball, blood everywhere. The Wall is a self-portrait showing a marine clinging with bleeding fingernails to a brick wall. Kellee said: “I think guilt is what killed him, what made him disconnect. He thought he’d let us down, let the families down, let the boys down who died, let the command down.”

Will’s journals were also full of morbid brooding. He quoted rock lyrics, with multiple underlining: “These broken dreams have GOT TO END.” To a girlfriend, he wrote: “There’s only a couple of options to get you out of my life: 1) Die 2) Make you hate me.” Kim Barron doesn’t think that Will was suicidal. “He was always crazy-overboard-protective [of his brother],” she said. Kellee thought the fraternal combination made the worst possible: “Tebeaux was a ticking bomb and Will was the fuse. I think Will helped Tebeaux make up his mind.”

What is broken, above all, with complex PTSD, is social trust, according to Jonathan Shay, one of its most astute analysts. Wounded warriors feel that they can trust nobody — not even their spouses. With loyal, self-destructive Will, Travis may have felt that he had found the one person he could trust, who would stay beside him to the end.

Did the Marine Corps abandon Travis? Kellee is reluctant to say too much about the Marine Corps’ role, since she and her daughters rely on military death benefits. Major Valerie A Jackson, a friend of the Twiggs family, wrote to the Marine Corps Gazette: “He should have been prevented from deploying again. A symptom of the disease is the overarching need to be in the fight. But there comes a point when someone with influence needs to say, ‘No, Staff Sergeant. Enough is enough…’ ”

Douglas Twiggs is unhappy that the Marine Corps did not intervene to change the course of the pursuit in Arizona. “They knew he had PTSD,” he said. “And yet they ran him down like a dog.”

On the morning of May 14, around 9am at a border-patrol checkpoint east of Yuma, almost 400 miles from the Grand Canyon, Travis and Will Twiggs were stopped for routine questioning. Forty-one hours had passed since they failed to drive into the gorge. Travis, wearing shorts, a short-sleeved shirt and no shoes, was driving. He presented his military ID, Will his Louisiana driver’s licence. The officers asked them to pull over. Travis floored it instead.

They headed east on the interstate. The white Dodge Caliber hatchback they had stolen didn’t handle well above 100mph. A border-patrol helicopter and other police cars joined the chase. Police radios crackled about the suspects. One transmission said: “Subject has ability to display emotion and then revert to military.”

Did Travis believe that he was back in Iraq? The desert zipping past, the sound of chopper blades, the hostile vehicles, the heat of the chase — the adrenaline rush had to be familiar. The speeding Caliber suddenly left the highway and headed north on Painted Rock Road. When the road ended, after 16 miles, at a dam, Travis pulled a high-speed U-turn and drove straight at his pursuers. They scattered without firing a shot. The chase continued. Travis seemed to have settled on a mortal determination not to be taken prisoner. Beer cans started flying out of the stolen car.

The road signs were now for Tucson and Casa Grande. The men had travelled 160 miles. On a long downhill stretch, great saguaro cacti stood on both sides of the highway. At Milepost 161, a policeman waited with a set of spike strips, having heard a call for assistance. The spikes blew out the car’s tyres. The Caliber hurtled and swerved down the highway for another mile before ploughing into a weed-filled hard shoulder and sliding to a halt.

Police surrounded the vehicle but kept their distance after they saw a revolver being waved from the driver’s window. Then they heard shots. Travis Twiggs had pulled the trigger three times. The first shot was fired at point-blank range through Will’s left temple, and it was fatal. The second was fired from under Travis’s own chin. The bullet came out through his left cheek. It was not fatal. The third shot, fired at point-blank range, went through his right temple — fatal. Will’s head had fallen back against the seat. Travis slumped into his brother’s lap.

The assembled officers approached the vehicle with extreme caution. For several hours, they worked to ensure that the crime scene was safe to enter. Having been told that Travis Twiggs was a combat veteran, their concern was that the car might contain an IED. It did not.

“My hardest thing is the last 10 minutes,” says Kellee Twiggs.

“I can’t understand that. Tebeaux would never hurt anybody. I can’t believe he would leave us, leave our girls.” She took several deep, ragged breaths. “But he really left us a long time ago. He tried to come back. But he couldn’t. That was not my husband out there.”

Originally published in The New Yorker

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