“That smell, if you’ve never been to a homicide scene, is the smell of death,” Phillips said, standing over Cuzco. He pointed out the killer’s signature: the blood around the head; the tooth marks where he’d crimped the windpipe, suffocating it; the open cavity, intestines removed. “I doubt he’ll be back tonight,” he said. “Ate enough from the body cavity. Probably gorged up asleep somewhere.” He showed me his weapons, a .40 Smith & Wesson Springfield XD tactical—a SWAT entry gun—and a semi-automatic Bushmaster. “The black rifles that the media hates so much,” he said.

In California, mountain lions have special protection. Although for much of the twentieth century the state paid bounty hunters to kill them, since 1990 trophy hunting has been banned. There is, however, a provision for “depredation permits”—permission, retroactive or in advance, to kill a mountain lion that threatens or attacks a person or his property. In 2015, a hundred and seven mountain lions were killed on depredation permits. The Vaughn-Perlings had lost nineteen animals to P-45. Victoria got a depredation permit from the California Department of Fish and Wildlife, and asked Phillips to execute it. He had experience.

Last spring, after the second attack on his place, Phillips took out his own permit to shoot P-45. Inside an old stall used for hay storage in the Western Town on his property, he had rigged a blind, cutting a window into a wall that looked over a pasture, where he left one of his dead alpacas as bait. For three freezing nights, he lay in wait, sometimes dozing off in the chair he’d dragged in, an elaborately carved wooden throne, which, Mary Dee Rickards said, had appeared in Errol Flynn’s “The Adventures of Robin Hood.” The alpaca started to stink. On the third night, at a little past one, Phillips startled awake to see an enormous creature leap over a five-foot fence. “I was not prepared for him to be as large as he was,” he told me. “He looked almost like an African lion, and his coat was almost as brown as deer hide. He was obviously an apex predator in the prime of his life. Not much body fat.” P-45 rolled the alpaca over with his paw as if it were a beach ball. Phillips took aim, but just as he fired P-45 ducked his head to eat.

P-45 fell to his side, and Phillips was sure he had delivered a mortal wound. But then P-45 clawed his way over the fence and into the surrounding bushes. After Phillips reported shooting him, Sikich, worried that he was injured, tracked him into dense undergrowth a quarter mile away, where he had hunkered down. When Sikich hiked in, P-45 took off, apparently unscathed. “We didn’t hear of a domestic animal being killed for two or three weeks after that,” Phillips said. “And then he started killing again.”

P-19’s kittens with P-45 were a female and a male, P-46 and P-47. Kittens typically travel with their mothers; mountain-lion fathers are more likely to kill their young than to train them. Courtesy National Park Service

The night of my visit to the alpaca farm was unusually cool, with the temperature dropping into the forties. Around 10 P.M., Victoria came out of the house, wearing prescription sunglasses—she’d mislaid her eyeglasses—a light shirt, and a skirt that flared around her knees. She whispered, as if the lion could hear. “If there’s something that’s aggressive, capriciously aggressive, and is attacking so many different people’s homes, eventually it’s going to be a child,” she said. She wished that the people who were actually responsible, whoever they might be, would move the lion somewhere else. “It’s not killing to eat,” she said. “It’s killing for the pleasure.”

To understand P-45’s behavior, though, one need not enter the psyche of a criminal mastermind. Just picture a cat, after dinner, toying with a ball of alpaca yarn. “This is a mountain lion being a mountain lion,” Sikich told me. “It’s programmed to jump on prey items. The only unnatural thing here is having non-native animals in a native animal’s territory unprotected.”

It is a message that he and his colleague Seth Riley have been trying to impart for quite some time. Months earlier, they’d scheduled a workshop for animal hobbyists living in mountain-lion country, in the hope of educating them about how to keep their animals safe. They had thought that fifteen people might attend, to see their demonstration of a lion-proof enclosure made with kennelling materials available at Home Depot. Instead, a few nights after P-45’s Thanksgiving spree, hundreds of people turned out for the workshop, ready to defend his life. Centuries of frontier history began to flow the other way.

“I hear P-22 is going to take a hit out on anybody who takes out P-45,” one man joked as he found a seat in a barn at the Paramount Ranch, a National Park property that once belonged to the movie studio. Activists had come from all over the state. One protester held a sign that said “Paws Up Don’t Shoot.” There was a tone of self-abnegation, and an inversion of Phillips’s resentment of the beast marauding his paradise. Humans were the interlopers, murderers, and thieves. “We invaded their home and their land,” a woman cried. At stake was the life of a lion they had come to adore—and the salvation he might represent for the entire mountain-lion population in the Santa Monicas.

“We need the DNA!” a woman shouted. “Keep the DNA in the mountains!”

“Is the homeowner aware that the extinction of mountain lions is on her head?”

Anyone who saw the matter differently was shouted down, deemed insufficiently wild to live among predators. “Go to L.A.! Go back to the city! Get out!”

After the workshop, Victoria pledged not to act on the depredation permit, but not without a bitter sense of having been victimized again, this time by P-45’s fans. P-45 was famous, and evidently he could do as he pleased.

The last best hope for the mountain lions of Los Angeles is a little strip of undeveloped land, a quarter of a mile wide, wedged between two housing developments on the south side of the 101 Freeway, at Liberty Canyon, in Agoura Hills. It is here, beside the freeway underpass that Sikich suspects was used by P-45, that the State of California plans to build a land bridge over the freeway, connecting the Santa Monica Mountains with the open space on the other side. Beyond it lie the Santa Susana Mountains and, farther still, the Los Padres National Forest, a three-thousand-square-mile wilderness that Sikich calls the Promised Land. The project, which will cost some fifty million dollars and is currently under environmental review, will be privately financed. Beth Pratt-Bergstrom, of the National Wildlife Federation, who leads the fund-raising effort, says she will walk across the bridge in 2021, no doubt with the cardboard cutout of P-22 strapped to her back. P-22, who has rallied the conservation community and the larger public around the need for connectivity, won’t benefit from a crossing. However, Sikich says, “the crossing will prevent other lions from potentially ending up in a dead-end spot the way he did.”

P-47, P-19’s male kitten, was captured in adolescence by biologists, who fitted him with a G.P.S. collar and released him. He measured seven feet from nose to tail and weighed a hundred and eight pounds—evidence of his father’s strong genes. Courtesy National Park Service

According to a preliminary design, an apron lushly planted with sweet-smelling mulefat and coastal sage will funnel animals up a gentle incline to the crossing, where the landscaped habitat will continue high above ten lanes of freeway, before depositing the animals, ideally none the wiser, in the open space on the far side. An extraordinarily complicated piece of engineering, the land bridge is based on a conceptually simple design. Back in the seventies, when this part of the 101 was built, a chunk of earth had to be removed to make room for the road; it was dumped nearby, and is still there today. To build the land bridge, the design proposes to take the dirt and put it back—only, this time, it will be suspended on pillars twenty-four feet above the road. Visually, the bridge will be a kind of truce, between the future we thought we wanted and the past we had.

When completed, the project will be the largest urban crossing for wildlife, a mega High Line for animals. Riley, who has been working on the crossing for fifteen years, told me, “It would be a very specific visual reminder that people in Southern California care enough about wild places and wild species to do this. Even in the second-largest metropolitan area in the country, we can do what it takes to preserve wildlife—the whole range, all the way up to and including mountain lions.”

Meanwhile, the animals are coming. For the past eighteen months, Sikich has been monitoring a series of cameras he installed in the underpass and in the natural habitat that will one day form on-ramps for the bridge. The cameras have captured bobcats, coyotes, raccoons, skunks, and deer. They have also captured two uncollared lions, one coming from the north, the other from the south. Each reached the freeway barrier and, finding it as yet too inhospitable, turned away. ♦