In 2012, when authorities caught 34-year-old Israel Keyes, a self-employed carpenter in Anchorage, Alaska, he was suspected of only one murder — that of a barista near his home. But as he was interviewed, the FBI suspected Keyes was a serial killer. Because he picked his victims at random — thousands of miles away from where he lived — the bureau’s top criminal profilers quickly designated his crimes as unprecedented.

In this second exclusive excerpt from “American Predator” (Viking), author Maureen Callahan recounts the tense scene in the interrogation room as agents sought another confession.

Days after confessing to the murder of 18-year-old Samantha Koenig in Alaska, Israel Keyes, hoping to strike a deal with prosecutors, said he would confess to a recent cold case that would otherwise never be solved — one clear across the country.

Keyes had been “two different people,” he told them, for 14 years, traveling all over the US for the sole purpose of killing.

As he spoke, the FBI’s case agents and behavioral analysts came to a terrifying realization: They had never encountered anyone like this before.

A Google Earth map of Burlington, Vt., was pulled up. As Keyes had with Samantha, he wanted to tell this story backward, starting with the end.

Watching and listening from another room, FBI agents Jolene Goeden and Kat Nelson Googled “Missing couple, Vermont” and found a picture of Bill and Lorraine Currier.

The photo was taken outside, under a tree. It looked like a picnic or a family gathering. They were a middle-aged couple, both dressed casually except for Lorraine’s corsage and Bill’s boutonniere. They were smiling, Bill’s arm around Lorraine.

They sent the picture to prosecutor Kevin Feldis.

“Are those the two people you killed?” Feldis asked.

“Yup,” Keyes said.

“Had you ever met them before?”

“Nope.”

“Had you run into them before?”

“Nope.”

On June 2, 2011, Keyes flew from Anchorage to Seattle to Chicago, where he rented a car and began driving east. He was going to visit his brothers in Maine, he said, but along the way, he stopped in Indiana for a couple of days, then at an old farmhouse he owned in upstate New York, then on to Burlington before reaching his final destination.

As Keyes approached this part of the story, he became physically excited, bobbing his knees, jangling his shackles, rubbing against his armchair so hard he scraped a layer of wood clean off. This would become another tell, his signature expression of sexual excitement. It would be the way investigators knew there was much truth to his story. Stories.

That night, Keyes waited until the sun went down, then left his hotel on foot. He carried a backpack of supplies, some brought from home. He’d unearthed other supplies earlier that afternoon from a cache he’d buried in Vermont two years before.

A cache? Feldis wanted to know what that meant.

Several years back, Keyes said, he had taken a five-gallon Home Depot bucket and filled it with zip ties, ammunition, guns and silencers, duct tape, plus Drano to accelerate human decomposition — things like that — and buried it there.

He had more buried all over the country. He’d get to that detail later. Maybe.

Keyes wandered around Burlington, his cellphone off, battery out. A little after midnight, randomly, he found himself looking at the house at 8 Colbert St. His years of experience in construction told him this was a simple-plan ranch.

He approached, crept around, found the phone line and cut it: no alarm system. He got the sense an older couple lived here, which was good, because he had an idea, one that required a woman. There was an above-ground pool and a barbecue in the backyard, no toys or floaties, no sign of children or pets.

Keyes was dressed head to toe in black. Strapped to his skull was an unlit headlamp. He broke in through the attached garage and, after rifling through the green Saturn sedan parked inside, found himself in the kitchen.

The whole thing took six seconds. A blitz attack, he called it.

At first, Keyes said, Bill, 50, and Lorraine, 55, didn’t understand what was happening. It took a few seconds for them to fully wake and realize: This wasn’t a nightmare. A large masked man with a gun, a total stranger, was really in their bedroom.

Lorraine had been sleeping in a T-shirt and shorts, Keyes said, but he took lingerie from her dresser drawer. Did he make her change clothes?

“I don’t know if I want to go into that,” Keyes said.

Keyes ordered Bill and Lorraine to roll over on the bed, on their stomachs, and zip-tied their wrists while barraging them with questions: Do you have a safe? Guns? Prescription drugs? Where’s your jewelry? ATM card? He demanded their PIN number and scratched it into the card’s surface, then grabbed two suitcases and began stuffing them with clothes and personal effects.

After 15 minutes, he told them they were all leaving the house.

He interrupted his story to brag a little. He never left physical evidence behind, ever. It was a point of pride.

“I seriously doubt you’re going to find DNA or fingerprints anywhere,” Keyes said.

He marched the Curriers out to the garage, putting Lorraine into the front passenger seat, hands still zip-tied behind her back, and belted her in. He restrained Bill the same way in the back passenger seat, then slowly drove the Saturn out of the garage.

They begged. Bill needed his medicine. They had no money. If he’d just let them go, he could take the car, the little cash they had — everything. They’d never tell a soul.

Oh, don’t worry, Keyes told them. This is just a kidnapping for ransom. I’m bringing you to a drop house. Other people will take it from there. You’ll be fine.

Inside his backpack was a pan, water bottles, 50 feet of coiled nylon rope, duct tape, latex gloves and one small propane stove.

It was around 4 a.m., quiet and dark, the road and sky horizonless when Keyes pulled up to an abandoned farmhouse off Route 15. That had been the reason for his drive earlier that day, to look at houses for just this moment.

The house he’d settled on had a FOR SALE sign staked in the brown grass.

“I always stop at empty houses,” Keyes said. “Especially if they have FOR SALE signs.”

Keyes cut the lights and ignition, leaving Lorraine tied in the front seat. He forced Bill through the basement’s outdoor entrance and down the stairs, tying him to a stool within minutes. Impassively, Keyes walked up and outside.

There was Lorraine, out of the car, standing up.

She saw him. She ran as fast as she could toward the main road, but Keyes was faster. He tackled her and dragged her back to the house, pushing her up the stairs and into a bedroom.

He strapped Lorraine’s arms and legs to the bed with duct tape, then wrapped a rope around her neck and under the mattress, tying it off with a compound knot. She fought the whole time.

Shouts came from the basement, echoing through the house. Where’s my wife? Where’s my wife?

Keyes checked his knots: secure. He grabbed a knife, his .40‐caliber revolver and his water bottle. He went down to the basement.

Why the water bottle?

“I’m not sure I want to get into that,” Keyes said.

Bill was partway free, the stool in pieces. The only light came from Keyes’ headlamp, the sight of Bill thrashing around as if under a strobe light.

“That pissed me off,” Keyes said. “Because there’s a very specific way I want things done, and I have the whole thing planned out. I have everything I need to do it.”

What were his plans for Bill?

“I’m not going to say what I was going to do to him.”

Investigators didn’t need to hear it. They knew: Keyes had planned to rape Bill, too.

“And so when somebody messes up that plan — it kind of surprised even me,” Keyes said, “that I lost control that way.”

He hit Bill with a shovel he’d found in the basement, but Bill didn’t go down. It took at least one more hit to knock him to the floor.

‘There’s a very specific way I want things done, and I have the whole thing planned out. I have everything I need to do it.’

Keyes ran upstairs. The propane stove he had set up had fallen through a hole in the bedroom floor. He panicked. The house was dry wood. It wouldn’t take much for it to flame up fast.

Incredibly, downstairs, Bill was back up on his feet and yelling.

Keyes ran back. He said he just started firing, like a reflex, shooting Bill in the arms, head, neck, and chest.

Bill Currier was still standing. Keyes had never seen anything like it.

Then, with his last breath, Bill fell to the floor.

Keyes went back upstairs to Lorraine. He lifted some of the freestanding doors and covered the bedroom windows, which faced the road.

Then he boiled water on the propane stove.

What was that for?

Keyes chuckled. “I don’t know if I want to get into that today,” he said.

He cut off Lorraine’s clothes with his knife, Lorraine still fighting. He raped her twice. Then he brought her down to the basement, where he sat her on a bench and presented his final scene: her husband, shot to death, lying in his own blood.

There was so much blood, Keyes said. That wasn’t a mistake he usually made.

He put on his pair of leather batting gloves. Then he stood behind Lorraine and strangled her with a rope. Even after he felt the life go out of her, he needed to make sure; this couple was tougher than Keyes could have imagined.

He wrapped a zip tie around Lorraine’s neck and pulled. Nothing.

Keyes was running out of time now. He dragged Lorraine’s body over to Bill’s and cut off their restraints. He poured Drano over their hands and faces, bagged each of their bodies in two 55-gallon trash bags, then rolled their remains over to the basement’s southeast corner, piling garbage and wood on top. He was in such a rush, he left all his shell casings on the basement floor.

The sun was up, people traveling Route 15 on their way to work. He had planned to burn the house with the bodies inside but it was too late. Not really a problem — he was sure that whoever eventually bought this house would do it for the property and tear down or torch it. The smell from the basement would be so putrid it would keep the most curious at bay — plus, the likely assumption would be that a wild animal wandered in and died. No, he was not worried about anyone finding the remains.

Keyes grabbed most of his stuff and drove the Curriers’ car to a nearby Rite-Aid parking lot, where he’d left his own rental the night before. He left the green Saturn as far from surveillance cameras as he could and walked to his car, head down and covered with a hoodie. Keyes got in and left the state, headed up to Maine.

Six hours, start to finish. And no one suspected a thing.

The FBI never found the Curriers’ remains. The house had indeed been torn down, the bodies unwittingly excavated and dumped in the local landfill. If Keyes hadn’t confessed, they never would have solved that crime, let alone have had any idea what happened to the Curriers, who, to neighbors and law enforcement, had simply vanished one dark night.

For the FBI, this horrifying story established Keyes as a new kind of monster, one they would come to suspect responsible for the greatest string of missing persons and unsolved murders in modern American history. How many other victims would they find?

Excerpted from “American Predator: The Hunt for the Most Meticulous Serial Killer of the 21st Century” (Viking), by Maureen Callahan, on sale July 2.