As a longtime fan of the television show Unsolved Mysteries, I remember a few times the late Robert Stack would introduce a mystery in South Dakota. In fact, there are 4 of them. Do you remember these cases that still have a lot of unanswered questions?

1. The Mystery in Lake Andes: The strange case of Arnold Archambeau, 20, and teenager Ruby Bruguier. In 1992, the young parents from the Yankton area, along with a 17-year old cousin, Tracy Dion, went on an all-night party spree. Early the next morning, December 12, Archambeau steered the car sharply into a frozen body of water in Lake Andes. Tracy was still inside the overturned car but Arnold and Ruby were nowhere to be found when paramedics arrived on the scene.

Did they go on the run fearing DWI trouble?

The next year, a passerby on a rural highway reported a body in the ditch. Authorities drained the ditch and found the bodies of Arnold Archambeau and Ruby Bruguier, but strangely the bodies were in different stages of decomposition. Several other odd clues about the scene do not add up and the case remained open until it was officially closed by the FBI in 1999. Ruby's father has maintained all along that he believed Arnold and Ruby were victims of foul play and the bodies had been moved there to make it appear to have been an accident.

The case first aired on Unsolved Mysteries in 1995. More details in the case can be found here.

2. Joseph Michael Swango - The 'Doctor of Death': A doctor who traveled around the country working at different hospitals, including the University of South Dakota Hospital, led authorities on a manhunt after has was suspected of over 60 patient poisonings. From the beginning of his career, Michael Swango was, by all means, a terrible physician. He was put on academic probation almost immediately in med school but found residency in the Ohio State Unversity Hospital. His suspected career of poisonings begins here as a 69-year old patient suffers a mysterious seizure. Then 5 other patients died. At one point, a nurse said she witnessed Swango leaving patient's rooms with an "evil smile on his face."
Swango was finally arrested and sentenced to 5 years in prison. Surprisingly, he went to work at the University of South Dakota Hospital where his past was finally brought up and promptly fired. It appears to have been the only hospital he worked at that didn't end in a mysterious death - but the poisonings continued in other locations where he practiced his evil medicine. Finally, after a segment on America's Most Wanted, Swango fled to Zimbabwe and was arrested in 1997. He's now doing life. The mystery? How was he able to kill over 60 people and avoid arrest? But the bigger mystery just maybe after leaving a trail of bodies and evidence, how did Swango keep finding work?

Learn more about the Swango case here.

3. The Vanishing of Tina Marcotte: The last time Tina Marcotte was seen was on the evening of June 24, 1994, in Rapid City, South Dakota. She worked a Black Hills Molding and got a flat tire on her way home from work. A man approached her and her vehicle and a man who said his name was Tom Kueter agreed to give her a ride. He told her he was a former forklift operator at Black Hills Molding. Tom didn't return home until 3:30 in the morning and his wife said he immediately began washing his clothes.
When Tina's car was found by authorities, they discovered that the tire had been slashed. The investigation eventually led to Tom and blood was discovered in his car. Kueter was on the hot seat with police building a case.
Tom was discovered the following morning with his head crushed by a forklift. Was it suicide? In an uncanny twist to this tragic story, the body of Tina was discovered under a lumber pile while Unsolved Mysteries was filming the episode.

Learn more about the case of Tina Marcotte here.

4. The Ghosts of the Hotel Bullock: In 1876, a year of unrest and lawlessness in the gold fever town of Deadwood, South Dakota, a new sheriff strolled into town. Seth Bullock was hell-bent on restoring order to the hottest little mining town in the Black Hills. Bullock bought an impressive hotel on Deadwood's Main Street and opened it in 1895. The previous owner had said that over 30 employees have had strange encounters and paranormal experiences while working in the hotel but Bullock pressed on. After over 100 years, the ghosts still appear to carry a grudge. Some employees in the 1980s were so frightened by ghostly figures they simply walked out the front door and never returned. The Bullock Hotel has also been investigated by several paranormal reality shows over the years.

Learn more about the Hauntings of the Bullock Hotel here.

Unsolved Mysteries got a reboot on Netflix and remains a very popular show.

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