Ann Riffin's parents suspected she might have run off to join a cult. Maybe a convent, they thought, or a commune.
Why else would their daughter, 33 years old and a native of New Jersey, disappear in a remote corner of New Mexico? Where else could she have even gone?
Thirty-five years after police found Riffin's car in September 1982 parked off a lonely, winding stretch of highway near Mora known as Holman Hill, those questions remain unanswered.
Riffin is still missing. Police have never found her body or any other sign of her. Riffin's family has not heard from her. Mostly forgotten, the case remains a mystery - a testament, perhaps, to the persistence of long-held secrets or at least the fact that even in an age when disconnecting from the world can seem unfathomable, the missing can still be impossible to find.
"She just landed there" in New Mexico, said Riffin's sister, Jane Susswein. "And there's no sense of what could have happened."
Why Riffin landed in New Mexico is something of a mystery in itself.
Riffin had a comfortable upbringing in the New York City suburb of Montclair, N.J. Her father was a respected family doctor and anesthesiologist. Her mother was involved in everything from the local temple to the board of education and public library. Susswein - older by four years - was Riffin's only sibling.
But Riffin was by all accounts something of an introvert. Family recall her as content to spend hours drawing. She kept to herself and no one seemed to remember her ever dating.
The family traveled - to Japan, to Europe. But as her father told the Albuquerque Journal's Impact Magazine in a 1985 interview, Riffin "had been around the world but was never worldly."
She attended Wellesley College in Massachusetts but dropped out after her junior year. She lived in New England, traveled to Britain, returned home and took up residence with her parents for a time before setting off on a bicycling trip.
Riffin's travels took her to Virginia, where she enrolled at the College of William and Mary in Williamsburg. She graduated and became a teacher, converted to Christianity from Judaism and worked at a school run by an evangelical sect.
The religious conversion displeased her parents, but Riffin eventually returned home to live with them.
She went from job to job before leaving again - this time to Israel. She wrote articles there for a Jewish newspaper back in New Jersey. And when she returned home, she looked for work as a journalist.
Riffin moved in with her sister, but her lack of direction seemed to trouble the family.
"She was a troubled girl," her sister recalled recently.
Riffin never settled down, never found her place in the world. Each journey seemed to be a search for meaning.
In 1982, she packed a few belongings in her car and left home again.
Her family suspected at first that she was headed for Pennsylvania, but she ended up going much farther, taking a job in a restaurant at a Ruidoso lodge.
She seemed to lead a quiet life there.
A local woman who rented a room to her told police that Riffin - 5-foot-4 with short brown hair and glasses - dressed plainly, never went out, did not have any boyfriends and was very quiet, even naïve.
Riffin had been in Ruidoso for only a few months when she left town for what turned out to be the last time in September 1982. It was not sudden. She had planned to visit relatives - her father's cousin and his wife - in Colorado Springs, Colorado, according to police reports. But she never arrived.
To her acquaintances in Ruidoso, it would be unlike Riffin to disappear without telling anyone where she was going.
But as her landlady told police: "I guess I didn't know Ann as well as I thought."
About 10 days later, New Mexico State Police found Riffin's white Chevy hatchback on a dirt road off the highway between Mora and Tres Ritos.
A rancher had called it in a few days earlier.
Former state police patrolman Herman Silva said there was nothing unusual about the car, except where it was parked.
It is a beautiful but mountainous and rugged part of Northern New Mexico.
What is now known as N.M. 518, but was then called N.M. 3, cuts through the heart of the Sangre de Cristo Mountains. Drive north from Holman Hill, and the road squeezes between sheer rock faces, past rushing streams and through bucolic meadows. Descend down Holman Hill, and the road gives way to the Mora Valley.
The first town at the bottom of the hill is Holman, an unincorporated community about 35 miles north of Las Vegas, N.M. Only 200 or so people live in its ZIP code.
The forest around there is plenty busy with ranching, firewood gathering and hunting. But it is not a tourist destination in its own right. It is not where you would expect to find a young woman from New Jersey spending much time.
So when officers checked the license plate and found the car was registered to Riffin's father, Irving, back in New Jersey, it seemed likely a fairly straightforward case of auto theft.
The case got much more complicated when investigators contacted the Riffins.
Susswein recalled that the phone call came between services for Yom Kippur.
"She'd had some issues," she said of her sister. "But she'd always been in touch. She'd always called."
Through talking with Riffin's parents, officers began to piece together a trip that had somehow led her to Mora County - and from there into thin air.
Why, Silva wondered, would Riffin leave her car where she did?
You can certainly get to Colorado Springs by passing through Mora. But it is not necessarily the fastest route.
"That's what was so strange," Silva said in an interview last month.
For Silva, now retired from his career with the New Mexico State Police, the Riffin case is a somewhat distant memory from his first years in uniform. Still, even after his career in investigation, and after all these years, Riffin's disappearance stands out as particularly odd to him.
"If [the car] broke down, you would pull it over to the side of the road," Silva said. "Where she left it, unless you were from around there, you wouldn't even know that place was there."
Besides, he continued, the vehicle seemed to be in working order and had a quarter tank of gas.
The car was locked and inside, police did not find any signs of robbery or theft.
Officers found paintings Riffin had apparently made. She had been taking art classes, acquaintances told police. There were clothes, too, along with paychecks and other ephemera of daily life, all apparently undisturbed.
The only thing that seemed to be missing was Riffin's purse. Her credit card did not appear to have been used after her disappearance.
Investigators searched the area. They brought in bloodhounds and rescue teams. But they turned up nothing. It had rained heavily in the preceding days, washing away any fingerprints on the outside of the car and complicating tracking.
Other leads ran out quickly.
An employee of a convenience store in the area reported seeing a woman - maybe Riffin - around the time she disappeared.
Other than that, no one seemed to remember seeing her. Police checked with hospitals, rehabilitation centers, women's shelters - all to no effect.
Meanwhile, Riffin's parents wondered if she had run off, perhaps back to a Christian sect or a cult. It would be a way to start over, to find a place where perhaps Riffin could fit in. And Northern New Mexico was dotted with communes.
Letters from members of the evangelical sect she had been part of in Virginia were found in her car. But Riffin's friends in the group said they had not heard from her. Silva visited a nearby commune. And at one point, investigators sent the Riffins a list of Catholic convents in the area.
The theory persisted, and a few years later, while pretty much every other explanation seemed to be a dead end, her family spotted a photo in People Magazine that showed a woman who resembled Riffin working as a nurse at an orphanage in Bangladesh.
It seemed to be a breakthrough, if only based on a slim hope.
The woman in the photo turned out to be someone else.
Silva has wondered if Riffin even left the car there or if perhaps it had been stolen from her and ditched at Holman Hill by someone else.
But, Silva said, why leave behind the car with just about everything else?
If Riffin had run off, family supposed she would get in touch some day. She had always kept in contact in the past. But as the years went by and her parents died, there was never a phone call.
"They never really gave up," Silva said, recounting that Riffin's parents kept in contact for years with him and his colleagues at the state police.
The last Susswein heard about the case was when a skull turned up in southern Colorado a few years ago. An investigator from the police department in Montclair, N.J., took a sample of her DNA in hopes the genetic commonalities between sisters would offer a clue - or, perhaps, bring closure. But it was not a match.
Susswein recalled visiting the area years after Riffin disappeared. She had been visiting New Mexico, saw Mora on a map and drove there with relatives. They met with one of the officers who had worked the case. They drove to where Riffin's car had been found.
And what struck Susswein was the vastness of the place.
"There's no comparison with the desolation, the remoteness of the country," she said.
In a strange way, the high pines of Mora County may have been a place Riffin would have loved - distant, remote, like the woman herself.
Perhaps that is what confounds those who knew her, those who have wondered what happened all those years ago.
Solving a mystery is usually a matter of connecting the dots. But in this case, it's as if there aren't any dots to connect.
Contact Andrew Oxford at (505) 986-3093 or firstname.lastname@example.org. Follow him on Twitter @andrewboxford. This story first appeared in the Santa Fe New Mexican, a sibling publication of The Taos News.