On the morning of December 12, 1992, just before sunrise, Arnold Archambeau, 20, and Ruby Bruguier, 18, left a car that Archambeau had been driving after an accident at an intersection near Lake Andes, South Dakota, United States. They left Bruguier’s 17-year-old cousin, Tracy Dion, in the car without explaining where they were going. Their location remained unknown for the next three months. One person later told police that she saw Archambeau at a New Year’s Eve party, but their families never saw the couple, who had a young child together.
In early March 1993, the bodies of Archambeau and Bruguier were discovered in a low area of land between the accident site and an old railroad path, a short distance from the road. The cause of death was determined to be exposure, but investigators believed the deaths were suspicious and did not occur immediately after the accident. The sheriff and a deputy from Charles Mix County visited the area during warmer months when there was little snow, but neither saw the bodies at those times. Other people in the area made similar statements.
Other details about the bodies suggested they may have died elsewhere or at different times. Bruguier’s body was identified by a tattoo because it was very decomposed. She was wearing the same clothes as the night of the accident, but without her shoes or glasses. Archambeau’s body, found underwater in the low area, showed much less decomposition. A set of keys found in his pocket did not match any house or car in the area.
A segment of the television series Unsolved Mysteries, filmed at the site, aired in 1995. The FBI took over the investigation but closed it in 1999 because no evidence of a crime was found. Local law enforcement who worked on the case believe that at the very least, the couple’s bodies were placed there after they died somewhere else.
Background
Arnold Archambeau, born in 1972, is a member of the Yankton Sioux Tribe. He grew up on the tribe’s reservation in the southeastern part of Charles Mix County, South Dakota. After his mother passed away when he was a teenager, Arnold was raised by his grandmother. At the time of his disappearance, he was living with his aunt and working at the Fort Randall Casino. Arnold played basketball at Marty Indian School, where he was selected to join a team of Native American students who traveled to the Soviet Union in 1990.
Ruby Bruguier, born on January 11, 1974, in Wagner, is also a member of the Yankton Sioux Tribe. She grew up on the reservation and attended school in Lake Andes, the main town of Charles Mix County. In 1991, Ruby and Arnold had a daughter together, though they did not marry.
Accident and disappearance
On the night of Friday, December 11, 1992, Archambeau and Bruguier took a break from their duties as parents and workers to spend time with friends. They left their daughter with Bruguier’s uncle and took Tracy Dion, Bruguier’s 17-year-old niece, with them. They visited several friends throughout the night. When they returned around 6:00 a.m. the next day, the uncle noticed they appeared to have been drinking. He suggested they return later in the day after they had become sober, which they agreed to do.
Later, near 7:00 a.m., the group was at a three-way intersection on U.S. Route 281 (also known as U.S. Route 18 and South Dakota Highway 50) about one mile east of Lake Andes. Archambeau, who was driving, stopped at a sign. As he turned left onto the road, the car hit a patch of black ice and overturned, coming to rest off the highway in a low area between the road and an old railroad track 75 feet north.
Dion later told Unsolved Mysteries that she did not see Archambeau leave the car after the accident, but he was not inside when the car came to rest upside down. Bruguier, she said, repeatedly said, “Oh my God! Oh my God!” and hit the car. Bruguier eventually pushed a door open and slid out. When Dion tried to do the same, the door was closed. She stayed inside the car until rescuers arrived later.
Archambeau and Bruguier did not return to the accident site. Deputy Sheriff Bill Youngstrom, one of the first responders, said he had other officers search the area near the road and the old railroad track after sunrise around 8:00 a.m. They looked for signs that Archambeau or Bruguier might have fallen off the road, slipped through ice in the low area, left clues, or walked onto the nearby frozen lake. No signs of the two were found. Youngstrom assumed they might return in a few days, as he had seen in other cases where drivers who had been drinking avoided criminal charges.
However, neither Archambeau nor Bruguier’s families reported that they had returned or contacted anyone. Youngstrom continued searching but found no clues. He, family members, and other officers searched a 100-by-25-yard area between Route 281 and the railroad track multiple times over the following weeks but found nothing. In late January, during a thaw that melted most of the snow in the area, a local man rode a horse up and down the same stretch looking for a missing hubcap. He did not find it and did not see anything unusual, according to Sheriff Ray Westendorf.
Discovery of bodies
By early March 1993, the couple's location was still unknown, and police asked the media to share the story in hopes of finding Archambeau and/or Bruguier. "This was a very unusual case," said Captain Vincent Merrick of the federal Bureau of Indian Affairs Police (BIAP). He was especially surprised by Bruguier’s apparent abandonment of a child she was still breastfeeding, which had never happened in any other case he had investigated. Investigators found no evidence that either person had serious conflicts with others or faced legal or financial problems. Merrick said he had asked the state’s Division of Criminal Investigation for help. The Archambeau and Bruguier families offered a $1,000 reward for any information that could lead to their discovery.
Within a week, on the morning of March 10, a motorist reported seeing a body floating in meltwater in the depression between Route 281 and the railbed, about 75 feet (23 meters) from the accident site. Deputies who arrived found the body of a young woman, so decomposed that it was only identifiable as Bruguier by a tattoo. They decided to pump the water out to check if Archambeau’s body was nearby and found it on the ground 15 feet (4.6 meters) away the next morning, under what had been 4 feet (1.3 meters) of water. It was less decomposed and easily recognized as him.
The difference in how much the bodies had decomposed, and their apparent absence for three months before being found, were not the only confusing details. Youngstrom told Unsolved Mysteries that a tuft of hair found on the roadside near the bodies was determined to be Bruguier’s, but it was in much better condition than it should have been if it had been there since the accident. Her body was wearing the clothes she had on at the time of the accident, but she was missing her shoes and glasses, he added.
Archambeau was fully clothed, but police could not confirm whether those clothes were the ones he was wearing on the morning of December 12. Neither his clothes nor his body were frozen to the ground, as they might have been if the body had been there over the winter. In his pocket, a set of keys was found—one for a car and two that appeared to be for a house. They did not match any vehicle or structure he was known to use or frequent.
Investigation
The bodies were taken to Sioux Falls, where the Minnehaha County coroner performed autopsies. The autopsies showed the individuals had not suffered serious injuries in the accident. The cause of death was determined to be hypothermia, but the exact time of death could not be determined. Days later, authorities said they believed Archambeau and Bruguier had died somewhere other than the accident scene. "One, they weren't there after the accident," said Charles Mix County state's attorney Tim Whalen. "Two, the bodies appeared on March 10 and 11."
At a March 19 news conference, family members of Archambeau and Bruguier, along with reporters, accused officials of racism and poor handling of the case. When asked if he had taken pictures of the accident scene, Youngstrom said he had but the negatives were ruined due to a processing error. "It sounds like you're trying to cover your mistakes," said Mike Archambeau. "It sounds like you didn't investigate properly." Bruguier's sister said Native Americans were "overlooked and set aside" in such situations. Archambeau's aunt added, "When a Native American is charged with something, it's pursued heavily. However, when a Native American is a victim, it's not pursued with the same effort." Despite these complaints, they agreed with Whalen that the bodies had not been at the scene since December and had been moved from another location.
Whalen also announced that police had spoken to a witness who saw Archambeau and Bruguier enter a vehicle heading east on Route 281 shortly after the accident. Bruguier was reportedly seen in Wagner on January 20. "We've not ruled out foul play, but we haven't ruled out other theories," Whalen said. The two were not listed in a national missing persons database because authorities believed neither would have left the area.
In November, police shared new information. After autopsies, evidence from the procedures (but not the bodies) was sent to a lab in New Mexico. The lab found results that differed from the autopsies, suggesting exposure might not have been the only cause of death. "I don't know if the differences are important," Youngstrom said. He did not consider the case a homicide investigation yet but wanted to know what happened. "Someone out there knows something, and I have to find that person," he said. One of Bruguier's aunts said the Sioux community believed foul play was involved: "I don't think anyone feels there wasn't foul play, and that's very frightening for a community." Quintin Bruguier, Ruby's father, wanted to know what happened to her mother so he could tell his granddaughter, whom he and his wife were adopting.
Two months later, police released more details. Youngstrom remained cautious. "I can't say I'm going to make an arrest tomorrow," he told the Sioux Falls Argus Leader. "All I'm saying is I can't rule it out yet." The New Mexico lab found additional evidence, but Youngstrom could not explain it further. He also said several people had contacted the sheriff's office, claiming they saw Archambeau and/or Bruguier after the accident and took polygraph tests. Youngstrom traveled to Nebraska to speak with former Lake Andes residents. The families increased the reward for information to $5,000.
A cousin of Bruguier's, living in Sioux Falls, thought the case might benefit from coverage by the NBC series Unsolved Mysteries. She contacted the producers, who agreed. In February 1995, the show sent a camera crew to Lake Andes. Police closed a mile of Route 281 so a stunt driver could re-enact the accident, with local actors playing the victims and first responders, including Youngstrom, who acted as himself. At the time, Youngstrom said: "We still don't have the three main questions answered: How did they die, because they didn't die at the scene? Where were they at? How did they get back?"
The segment aired two months later. Dion described the accident and how Archambeau and Bruguier disappeared quickly without speaking to her. Youngstrom revealed he still had the keys found in Archambeau's pocket and had not yet found the matching locks or vehicle.
Youngstrom and BIAP Dennis Simmons traveled to California to take calls from viewers offering tips after the show. "I'm excited about getting started and following up," Youngstrom said. About 25–30 calls were received, mostly from South Dakota, but some from Oklahoma and Wisconsin. "It was at a standstill, and now we've got something to look forward to," Simmons said. One call from outside Charles Mix County came from someone who worked in the area and claimed to have seen one of the victims; "He's supposed to come in this week."
After the segment, police shared more details. A woman who knew Archambeau said she saw him on New Year's Eve and passed a polygraph test. A couple who claimed to have been in the car that night denied it but failed their polygraphs. Youngstrom also checked a call from North Dakota about two men seen near a "Blazer-type vehicle" at the accident site the morning the bodies were found.
None of the leads from Unsolved Mysteries helped solve the case. Later that year, a lawsuit over reservation boundaries led to a temporary court order that limited state and local law enforcement jurisdiction over part of Charles Mix County. The FBI then took over the investigation.
Four years later, the FBI closed the case, finding no evidence of a crime. "There isn't any indication of anything else beyond their deaths," said FBI Special Agent Matt Miller. "All we know is that they appeared in the ditch and that was it."
Law enforcement did not actively investigate the case in the 21st century, but the sheriff at the time, Westendorf, remained convinced questions remained unanswered. Upon his 2011 retirement, Westendorf told a local newspaper the case was the most puzzling of his career. He recalled a horseback rider who searched for his missing hubcap in late January 1993. With warmer weather, the area near the road and railbed was dry and bare, but the rider found neither the hubcap nor the bodies, even though they were recovered a month later.
"I believe they were placed in the ditch after they passed away somewhere else," Westendorf said. "I do know they weren't there in January. It's hard to prove someone was murdered without evidence."
In 2019, Beresford author Christine Mager Wevik wrote a book, Someone Knows, about cold cases in the