Bonus: The Causey Search

A mound of rocks sat undisturbed on a narrow mountain ridge, as it had for many years.

Human hands had stacked these rocks, but for what purpose? The dimensions of the mound were notable: roughly six feet long by three feet wide. About the size one might expect to see for a makeshift memorial placed over a clandestine grave.

This pile of rocks, unremarkable on its own, stood out when considered in context with evidence from two 1985 missing persons cases: the disappearances of Joyce Yost and Sheree Warren.

Causey Estates rock pile possible clandestine grave
An anomalous rock pile on a mountain ridge southeast of Causey Reservoir, as it appeared in May, 2023. Photo: Dave Cawley, KSL Podcasts

COLD discovered the Causey rock pile while researching the Yost and Warren cases. The appearance of this unexplained pile of rocks on a mountain ridge a couple of miles southeast of Causey Dam prompted speculation among investigators.

Could it mark a burial site for one of these missing women?

Joyce Yost and Sheree Warren

Joyce Yost disappeared from her apartment in South Ogden, Utah on the night of Aug. 10, 1985. Evidence would later show a man who’d previously sexually assaulted Joyce, Douglas Lovell, killed her to prevent her from testifying at his upcoming trial. Lovell admitted to driving Joyce east into the mountains and leaving her body at an undiscovered location.

Joyce Yost, a 39-year-old mother of two, vanished from her apartment in South Ogden, Utah on the night of Aug. 10, 1985. Photo: Joyce Yost family

Several weeks later, on Oct. 2, 1985, Sheree Warren left an office building in Salt Lake City, Utah. She reportedly told a coworker she was headed to meet her estranged husband, Charles Warren, at a nearby car dealership. Sheree then planned to take her 3-year-old son to her parents’ house in the community of Roy, a suburb of Ogden, Utah.

Sheree didn’t make it home that night, or ever again. Six weeks later, her maroon Toyota Corolla surfaced behind the Aladdin Hotel and Casino on the Las Vegas Strip. Police couldn’t say how the car ended up there, or what might’ve happened to Sheree.

Sheree Warren, a 25-year-old mother co-parenting a 3-year-old son while going through a divorce, was last seen Oct. 2, 1985 outside an office building in Salt Lake City, Utah. Photo: Sheree Warren family

Roy police, who led the investigation into Sheree Warren’s disappearance, harbored suspicions about two men. They investigated her estranged husband, Charles Warren, who had a history of domestic violence against his first wife. Detectives also wondered if Cary Hartmann, a former Ogden Police reserve officer whom Sheree had been dating, might’ve been somehow involved.

But why would investigators presume to look for either of these women near Causey, a small and somewhat obscure reservoir tucked into a narrow canyon 20 miles east of Ogden?

The Case for Causey

An anonymous man called Roy City on April 3, 1987, roughly a year-and-a-half following the Joyce Yost and Sheree Warren disappearances. The man told a dispatcher he’d located a body. Upon learning the body sat outside Roy’s boundaries, the dispatcher instructed the man to instead call the Weber County Sheriff’s Office.

The anonymous caller did so. In a stammering voice, the man explained he’d been searching for “rock sediments” in the mountains near Causey Dam when he’d stumbled upon the decomposed remains of a woman.

Causey Reservoir bank shoreline canyon
Causey Dam impounds the South Fork Ogden River. Several trails access the steep shores of the reservoir, as seen here on Sept. 18, 2022. Photo: Dave Cawley, KSL Podcasts

“I didn’t touch the body or anything because I didn’t want to get fingerprints on it,” the man said according to a recording of the call, “but I noticed there was a purse there.”

Dispatcher Sheli Tracy pressed the anonymous man for details, but the man remained vague. He said only that to reach the spot he’d parked at the dam and gone 2 or 3 miles back, crossing a “couple of ravines” to an area that very few people go into. Tracy asked the caller to remain on the line while she grabbed another person more familiar with the area. The caller agreed to wait, but hung up when briefly placed on hold.

Winter snow still covered the mountains around Causey at that time in early 1987. Police made a preliminary search within days of receiving the anonymous call, but were not able to go far beyond Causey Reservoir.

Searchers tried again two months later, in June.  By that time, police in Ogden had identified Sheree Warren’s boyfriend, Cary Hartmann, as a suspect in a years-long string of sexual assaults. In May of 1987, the Weber County Attorney’s Office filed felony charges against Hartmann in connection with four of those cases. Ogden police arrested Hartmann on a warrant, and word of his arrest made the news.

As the story of Hartmann’s arrest spread, new witnesses began coming forward. Some of them claimed Hartmann and Sheree Warren had been together on the night Warren disappeared.

Detectives from Ogden and Roy also learned Hartmann had at least three close personal friends who owned lots in Causey Estates, a cabin subdivision adjacent to Causey Reservoir.

A brief history of Causey Estates

Access to the mountainous area surrounding modern-day Causey Reservoir has long proved difficult.

The first known vehicle crossing of the mountain south and east of Causey occurred in September, 1924. A story published in the Ogden Standard-Examiner described a journey by two surveyors who were seeking to find a shorter route between the cities of Ogden, Utah and Evanston, Wyoming.

“In the county truck they turned off the main highway at Devil’s Slide, went up Lost Creek and then north to Magpie Flat,” the story read, “westward across the flat and down Magpie Canyon to South Fork Canyon, just above Ogden.”

Ten years later, in 1934, an engineer-turned-rancher named Irvin Jacob purchased the majority of that same mountain. Jacob managed the land through his company, Basin Land and Livestock. In the years that followed, Basin Land and Livestock improved the primitive route through Magpie Canyon, using it to shuttle sheep herds to summer range high on a plateau known as Magpie Flat.

Historical maps and aerial photographs show as far back as the 1940s, an unimproved ranch road crossed Skull Crack Canyon, which is today home to Causey Estates. That road traversed Skull Crack from west to east, climbing out of the canyon by way of an unnamed ridge.

Skull Crack Canyon aerial image 1953
This June 25, 1953 U.S. government aerial photograph shows Skull Crack Canyon. A sheep herder road connecting South Fork Canyon to Magpie Flat is visible crossing from the top-left to bottom-right of this image.

In 1962, the U.S. Bureau of Reclamation began construction of Causey Dam, near the confluence of the South Fork Ogden River with its tributaries of Skull Creek and Causey Creek. The reservoir impounded by the dam was first filled in 1966.

A couple of years later, Basin Land and Livestock cut a road from the newly constructed Causey Dam into Skull Crack Canyon. The company began charging hunters a small fee to use this new road to access prime deer and elk habitat on the hills and canyons behind Causey Reservoir.

Causey Estates Skull Crack Canyon hunting cabin newspaper advertisement
During the 1960s and 1970s, Basin Land and Livestock opened a portion of its property near Causey Reservoir to the public, both for hunting and eventually for the construction of cabins in a subdivision called Causey Estates.

By the early 1970s, Basin Land and Livestock had secured permission from Weber County to subdivide a portion of its property in Skull Crack Canyon. The new subdivision was named Causey Estates.

Development of Causey Estates occurred in three phases. Lots in phase 1 first became available in 1974. Phase 2 followed a short time later, in 1976. The third and final phase was not opened until 1983.

By the time Joyce Yost and Sheree Warren disappeared in 1985, many cabins dotted Causey Estates phases 1 and 2.

The U.S. Geological Survey published an update to its 7.5-minute Causey Dam quadrangle map in 1981. The revision showed the addition of new roads and structures in Skull Crack Canyon, as a result of the development of the Causey Estates subdivision.

Phase 3, tucked in a side canyon on the far eastern edge of the development, remained comparatively primitive. But lot owners at Causey Estates would often use the old ranch road that departed from phase 3 going toward Box Spring and Magpie Flat to access hunting ground in the vast, undeveloped Basin Land and Livestock property.

Cary Hartmann’s connections to Causey

Police gathered evidence in the Sheree Warren case during 1987 that showed Warren’s boyfriend, Cary Hartmann, knew the Causey area well. Hartmann had several friends who owned lots in Causey Estates.

C. Brent Morgan had known Hartmann since childhood. They’d grown up together in the Uintah Highlands area of Weber County. Morgan, a taxidermist by trade and an avid hunter, had been one of the first buyers when lots became available in Causey Estates.

For Morgan, a primary perk of owning land in Causey Estates was the promise of hunting access on the adjacent Basin Land and Livestock property.

“In the early years, the advantage was it was very isolated,” Morgan said in an interview for COLD.

Morgan began construction on a cabin in the early 1980s. The work progressed slowly over the course of several years. By 1984, Morgan was ready to install plumbing at his unfinished cabin.

“Guess who did the plumbing work. Cary did,” Morgan said.

Hartmann came from a family of plumbers and was himself a licensed plumber.

Cary Hartmann plumbing license
Cary Hartmann maintained a professional license as a journeyman plumber in the state of Utah. In September of 1984, Hartmann performed plumbing subcontracting work at his friend C. Brent Morgan’s cabin in Causey Estates.

Hartmann’s own 1984 daily calendar, obtained by COLD from police evidence, showed he spent several days during September of 1984 at Morgan’s cabin in Causey Estates. Hartmann also attended Morgan’s wedding at Box Spring, just outside Causey Estates near Magpie Flat, on Oct. 7, 1984.

Box Spring sat along the old ranch road that connected Causey Estates phase 3 with Magpie Flat.

“He knew the gate system,” Morgan said. “He knew how to get to my place, he could drive the roads.”

Following Hartmann’s arrest in 1987, Morgan told police Hartmann had borrowed his key for the gate at Causey Estates in September, 1985, a couple of weeks prior to Sheree Warren’s disappearance. Handwritten detectives noted obtained by COLD show Morgan told police “that he did not get his key back until Oct. 11, 1985,” more than a week after Warren vanished.

Cary Hartmann Box Spring Brent Morgan
Cary Hartmann, in black, approaches C. Brent Morgan, center, at Box Spring on Oct. 7, 1984. Morgan hosted is wedding at the remote spring southeast of Causey Reservoir. Photo: C. Brent Morgan

Another of Hartmann’s friends, an elk hunting guide named Allen Fred John, told police he’d bumped into Hartmann and another man in a clearing at the head of Guildersleeve Canyon on Sunday, Oct. 6, 1985. John had reportedly questioned Hartmann, wondering why he was trespassing on private property during the opening weekend of the annual elk hunt.

The location at the top of Guildersleeve Canyon described by John sat east of Magpie Flat and could’ve been accessed through Causey Estates.

Guildersleeve Canyon Cary Hartmann sighting
This May 27, 2022 image captured from KSL Chopper 5 shows the location where elk hunting guide Allen Fred John told police he spotted Cary Hartmann trespassing on private property four days following Sheree Warren’s disappearance. The dirt road visible in the image is accessible from Causey Estates. Photo: Dave Cawley, KSL Podcasts

Police spoke to yet another of Hartmann’s friends in 1987, a former Ogden police officer named Bill Thorsted, whose family owned a lot in Causey Estates phase 1. Records detailing that conversation have been lost by the Ogden City Police Department.

Most significantly, Hartmann’s friend Dave Moore owned a lot in Causey Estates phase 3. Hartmann had told Roy police he’d spent the evening of Warren’s disappearance with Moore at a bar in Ogden. But when police questioned Moore, they learned his timeline and Hartmann’s conflicted.

Doug Lovell and Joyce Yost “up by Causey”

In 1991, a South Ogden detective named Terry Carpenter questioned Douglas Lovell’s ex-wife, Rhonda Buttars, about the disappearance of Joyce Yost. Buttars told Carpenter that Lovell had murdered Yost to prevent her from testifying at trial.

Buttars provided a recorded statement to police, in which she described what Lovell had told her about Yost’s murder.

“[Lovell] said he made [Yost] drive up the canyon and they went up by Causey and he said he didn’t go far off the road,” Buttars said. “He just stopped the car and got out of the car and walked up this hill and it wasn’t very far off the road and grabbed her neck and was choking her and then I think he stepped on her neck and stomped on it and smashed it.”

Buttars said Lovell had tried to bury Yost’s body as best he could.

“He said he didn’t bury her very deep. He just, you know, like put leaves or shrubbery or dirt over her,” Buttars said. “She had her purse at the time, he said, and he dumped all her stuff out by her, her purse and then just left it.”

Douglas Lovell poses for a booking photo at the Salt Lake County Jail on July 9, 1985. Jail staff released Lovell shortly after this photo was taken, in violation of a judge’s hold order. Lovell murdered Joyce Yost a month later. Photo: Salt Lake County Sheriff’s Office

Prosecutors twice had Buttars wear a hidden recording device as she visited Lovell at the Utah State Prison. In those two recordings, obtained exclusively by COLD, Lovell made incriminating comments about how and why he killed Joyce Yost.

“I am the only one that knows where she’s at,” Lovell said in one of those recordings.

Lovell said he’d revisited Yost’s body some time later, better concealing Yost and stealing a wristwatch he’d initially left with her remains. Lovell expressed confidence no one would find the gravesite.

“The only thing I’m nervous about is that one time that caller called in,” Lovell said, in reference to the anonymous caller who’d reported finding a woman’s body near Causey Reservoir.

Prosecutors used Buttars’ confession and Lovell’s recorded statements to obtain a capital murder charge against Lovell in 1992. Lovell entered into plea negotiations, hoping to avoid a potential death sentence. During the summer of 1993, Lovell led police to a site along the Old Snowbasin Road east of Ogden where he claimed to have buried Yost. Searches of that site failed to turn up any human remains.

Douglas Lovell told police he’d buried Joyce Yost in a shallow grave near this spot along the Old Snowbasin Road in Weber County, Utah. The site, seen here on May 8, 2021, was searched extensively during the summer of 1993 but no human remains were located. Photo: Dave Cawley, KSL Podcasts

The Old Snowbasin Road site was nowhere near Causey Reservoir, where Buttars had told police Lovell claimed he’d taken Yost the morning following the murder.

Lovell’s failure to produce Joyce Yost’s remains invalidated his plea agreement. A judge sentenced Lovell to death. Lovell’s case remains under appeal.

In 2021 and 2022, COLD attended a cadaver dog searches of a cabin property previously owned by Lovell’s parents in Sunridge Highlands, a subdivision about eight miles northeast of Causey Reservoir. Those searches did not lead to the discovery of Joyce Yost’s remains.

Finding the Causey rock pile

COLD began collecting historical maps and aerial images of the Causey area while researching the Joyce Yost and Sheree Warren cases. COLD also tasked Chopper 5, a news helicopter operated by KSL 5 TV, with gathering video of specific sites around Causey.

On Dec. 9, 2019, Chopper 5 recorded video of an unnamed ridge east of Causey Estates phase 3. Close examination of the video revealed the presence of a rock mound, located about 40 yards to the side of the disused Basin Land and Livestock ranch road that once connected Causey Estates with Box Spring.

KSL Chopper 5 video showing an anomalous rock pile on a ridge near Causey Reservoir on December 9, 2020.

COLD conducted further research in an attempt to determine when the rock pile was first constructed. A review of historical aerial images showed the mound was present as far back as the early 1990. Images generated prior to that time were not clear enough to conclusively show the mound.

Chopper 5 collected additional video of the rock pile during flyovers of the Causey area in May and September of 2022.

KSL Chopper 5 video of an anomalous rock pile on a mountain ridge near Causey Reservoir on September 22, 2022.

The rock pile sat less than half a mile as the crow flies from the lot in Causey Estates phase 3 previously owned by Cary Hartmann’s friend, Dave Moore.

Causey Estates rock pile Dave Moore property
A U.S. government aerial image captured on Sept. 12, 1986 shows the relative positions of Dave Moore’s former lot in Causey Estates phase 3 with an anomalous rock pile identified by COLD. Annotations added by COLD.

It was about 2.5 miles from Causey Dam, which was consistent with the description provided by the anonymous caller in 1987.

As a result, COLD provided images and GPS coordinates for the rock pile to Roy City police.

Police search of the Causey rock pile

Roy police, in cooperation with Weber Metro CSI and the Weber County Sheriff’s Office, conducted an excavation at the site of the rock pile on Aug. 23, 2023. COLD accompanied the investigators to the site and observed their work.

Weber County CSI Causey rock pile search
Weber Metro CSI staff, along with Roy City police and Weber County search and rescue staff, examine the rock mound near Causey Estates on Aug. 23, 2023. Photo: Dave Cawley, KSL Podcasts

Over the course of several hours, detectives removed the rocks and scraped out the soil beneath them. They painstakingly removed the earth a few inches at a time. CSI staff then passed the dirt and pebbles through a mesh screen, watching for any items of evidence.

CSI sifting dirt through mesh screen
Crime scene investigators from Weber County sift dirt, pebbles and vegetation on a mesh screen at the site of a suspicious rock mound near Causey Reservoir on Aug. 23, 2023. Photo: Dave Cawley, KSL Podcasts

The mesh was designed to capture any bone fragments, teeth or cloth scraps that might be expected to come out of a clandestine grave. Bucketful after bucketful went through the screen. Fine sifted dirt collected in a growing heap on a blue tarp beneath the screen.

Causey rock pile screen sifting clandestine grave
Dirt sifted by Weber County CSI sits on a blue tarp next to the former site of a suspicious rock pile near Causey Reservoir on Aug. 23, 2023. Police determined the site did not hold human remains. Photo: Dave Cawley, KSL Podcasts

By midafternoon, the excavation reached a depth of roughly 2.5 feet below ground level. The detectives at that time noted they’d entered a soil layer that had not been previously disturbed. No evidence of human remains had been located. The investigators concluded the site was not a clandestine grave.

Roy police detective John Frawley told KSL TV it was a disappointing result, but worth the effort.

“You’re always hoping to find something,” Frawley said. “We keep going. If there’s a place to dig, we’re going to dig. If there’s a place to search, we’re going to search. And we’re just not going to stop.”

Hear what happens next for the Sheree Warren investigation in a bonus episode of Cold season 3: The Causey Search

Episode credits
Research, writing and hosting: Dave Cawley
Audio production: Aaron Mason
Audio mixing: Ben Kuebrich
Cold main score composition: Michael Bahnmiller
Additional scoring: Allison Leyton-Brown
KSL executive producer: Sheryl Worsley
Workhouse Media executive producers: Paul Anderson, Nick Panella, Andrew Greenwood
Amazon Music and Wondery team: Morgan Jones, Candace Manriquez Wrenn, Clare Chambers, Lizzie Bassett, Kale Bittner, Alison Ver Meulen
Episode transcript: