Mike Petersen disappeared June 4, 2017. Body found June 7 2017, Beaver Creek/ West Fork area, West Yellowstone, Montana.

Revised and expanded September 2024

On June 4, 2017, 42-year-old Mike Petersen kissed his girlfriend, Bonny Senger, goodbye at the West Fork Beaver Creek Trailhead near West Yellowstone at 9.30 am as he set off for another attempt to locate the Forrest Fenn Treasure.

Mike, a father of four with kids aged 17-23, was a frequent hiker in the Montana Rockies and Yellowstone National Park area and had headed out on treasure hunts on several occasions.

On that day, he was wearing a bright orange vest and waders and carrying a gun. He also packed supplies such as food and bear spray. He would often visit with one or more of his children, but on this occasion, he decided to go solo hiking.

Mike texted Bonny throughout the day as he knew where he could get cellular reception. She planned to pick him up around 6 pm at the trailhead and go for dinner.

But when Bonny arrived, there was no sign of Mike. She waited and searched the area around the trailhead. At 7:20 p.m., she claimed she heard four gunshots in the woods and reported to family members that she had met a group of bear hunters in the area who had also reported the shots during their brief conversation. Relieved, she hoped it might have been a signal that he was on his way, but then there was nothing, even after hours of waiting. But he didn’t show up.

Mike’s body was recovered from Beaver Creek three days later after apparently drowning. Gallatin County Sheriff's Captain Jason Jarrett said, "Bad things happen to good people, and nature doesn't care that 99 times out of 100, it went OK. Water in itself needs to be respected. Moving water is deceivingly powerful".

Jarrett said Petersen likely died attempting to cross the creek on his way back to the trailhead in the afternoon. Due to the spring snow melt, the creek was much higher than it was when Petersen crossed it in the morning.

However, some family members have cast doubt on the Sherrif’s office’s version of events for this experienced and well-prepared hiker and claim that foul play was more likely involved.

The Hike

At around 9:30 a.m. on Sunday, June 4, 2017, Mike Petersen headed off down the trail near Beaver Creek in the West Yellowstone area.

His girlfriend of three years, Bonny Senger, 53, said after the incident in an interview, "I never wanted him to go alone. That always scared me. But you don't question. I guess I didn't really know how dangerous it was. The last thing I said to him was, I don't know why I said it. I said Philippians 4:13. I can do all things through Christ.”

Bonny and her 14-year-old son, Jace, drove to nearby Yellowstone National Park to watch the buffalo and see Old Faithful geyser.

Who was Mike Petersen?

Bonny Senger Selfie with her boyfriend Mike Petersen — Bonny Senger twith her boyfriend Mike Petersen

Michael R. Petersen was born November 26, 1974, in Seattle, the son of Sheila (Baum) and Ronald Petersen. Unforturnately he lost his mother at the age of 15.

He had four children (aged 17 to 23) with his ex-partner, Corinna McLaughlin: Riese, Chance, Valerie, and Savear McLaughlin. They lived in Bismark, North Dakota.

Mike loved music and lived for sports. He wasn't afraid to belt out a song in public and sing along with the radio. He knew the words to every song! He was an avid football, basketball, and hockey fan and a strong swimmer who could hit a baseball like no other. Athletic and strong, Mike was also ambidextrous, which earned him the nickname "Left" because he could shoot or hit a ball on both sides just as well.

He loved animals, and they loved him, especially his special Pitbull "Kilo".

He was a "jack of all trades" and made everything look easy. A welder by trade, he also built custom fences.

Mike loved to hunt, fish, and enjoy nature. Before his death, he wanted to complete his faith journey with the Catholic Church, so he attended catechism classes at St. Anne Church and was confirmed.

As his family said in his obituary, “The twinkle in his eye…the sound of his laugh, his awesome hugs…we will forever miss him. He was our Protector, our St. Michael in the flesh.”

The search

Bonny planned to pick Mike up at the trailhead at around 6 p.m. they were planning to get dinner and make a fire before bedtime. But there was no sign of Petersen.

At around 8 p.m., Bonny quickly drove to find cell service to call the Gallatin County Sheriff's Office. At 10 pm that day, a search was started with a search-and-rescue team, sniffer dogs, and helicopters.

Initial search activity included personnel from the West Yellowstone division of Gallatin County Search & Rescue, Hebgen Basin Rural Fire District, Air Methods helicopter and Two Bear Air Rescue Helicopter from the Flathead County Sheriff’s Office. Air Methods conducted an initial search by air until rainy weather forced them to land. Two Bear Air picked up the air search a few hours later using FLIR (Forward Looking Infrared Radar) throughout the early morning hours of Monday, June 5. Air efforts continued throughout Monday with Two Bear Air, while they also assisted in moving ground resources into the designated search zone.

On Monday, the ground search efforts comprised twenty-five individuals from Gallatin County Search & Rescue crews from West Yellowstone, Big Sky, the Gallatin Valley, National Forest Service Personnel from Hebgen Basin Rural Fire District, and three K-9 dog search teams.

The next day, continued search efforts involved the same personnel from earlier, with additional air resources from Central Helicopter and ground teams from Madison County SAR, Ruby Valley SAR, and the Department of Livestock. In total, forty ground searchers looked for Mike.

During their search, rescuers found Petersen's vest and bear spray canister about a half-mile away from the river. Crucially, they also found his backpack with his gun. But they couldn’t locate Mike.

Remains found

West Fork Beaver creek trailhead sign — West Fork Beaver Creek TrailHead

Then Mike was found drowned in Beaver Creek on June 7, 2017, at 11.30 a.m. by a search team, including a K9, after three days of efforts. The body was located a quarter mile south of the confluence of the Beaver and West Fork Creeks.

Gallatin County Sheriff's Capt. Jason Jarrett said Petersen likely died attempting to cross the creek on his way back to the trailhead in the afternoon. Due to the spring snowmelt, the creek was much higher than it was when Mike crossed it in the morning. The Gallatin County rescue team has responded to three drowning deaths that spring.

Mike’s brother, Mac Petersen, a 27-year-old cook and server at Rolling Hills in Mandan, drove to southern Montana to join the search when he learned of the incident the day after he went missing. Mac said he last spoke with Mike three days before his death. Knowing Mac Petersen was worried about his safety while hiking alone, Mike Petersen lied, saying he was going to a wedding in Denver while treasure hunting in the wilderness. Mac said, "He wasn't necessarily the most honest with people, but it was because he was always trying to make everybody happy”.

Beaver Creek West Yellowstone — West Fork Beaver Creek Trail

What happened to Mike Petersen?

The big question is why Mike, an experienced outdoorsman, left his kit behind and headed for the dangerous creek. With bears around, leaving his firearm and spray would have been particularly reckless. Several people have been killed or injured in the Yellowstone area by Grizzly Bears. Was there more to the story than the police reported? Was it a simple drowning, as Gallatin County Sheriff's Capt. Jason Jarrett quickly concluded?

Potential Foul play?

According to Valerie McLaughlin, Mike’s daughter, she stated to StrangeOutdoors in correspondence that:

“I'm positive that Bonny Senger had a hand in my dad's death. There are messages between Bonny & on an old Verizon account that is no longer active, but I'm hoping that there is a way, especially if pressed by the law, that the account can be looked Into to retrieve the messages between Bonny & me that prove she's hiding something considering she left it out of her report & tho she did she made one mistake,”

“On the evening of June 4, 2017, when my dad didn't make their rendezvous, Bonny had called me, and we were texting, keeping contact about the whole thing & she sent me messages stating something that had happened before she called the park rangers & it doesn't make sense none of it then a couple of mo the later Bonny tells me "what? I never said that, Valerie. That never happened." But I have the text messages from Bonny’s phone number, Verizon, that she still uses today & it is on that old Verizon account & the person whose account I was on is still alive & well today but says she hasn't been with Verizon for a couple of years now and apparently doesn't know how to go about getting those messages retrieved.”

“Bonny Senger told me about 30 min after Dad didn't show up, she started calling his name. Then she heard the gunshots, still calling his name. She said three men walked out of the woods and came her way. Bonny then told me, "Really nice guys, Val. They said they heard the gunshots, too, but didn't see anyone. They even went back into the woods & called ur dad's name for about 10 minutes, but there was no response. Real respectful, really nice guys, they were hunting bears. One of them had recently gotten out of surgery. I immediately asked Bonny what their names were & she said, "I didn't get their names." I said are you fucking kidding me? Dad's is practically missing. You’re worried that he didn't make it on time & SHE KNEW Dad was looking for the Forrest Fenn treasure. That's the ONLY REASON dad was out there 4 or 5 other times. He wasn't just hiking because he liked to do so; he was looking for the treasure & his girlfriend financed the whole thing. Dad even asked me if he should even tell Bonny about it because we had no money, but Bonny was rich. Dad said he could go now or later when he could finance his trips. My oldest brother and I told him to tell her.

“I talked to my Dad's lawyer about it. His name is Justin Vinji, out of Bismarck, ND. & he told me, "If these three men WERE hunting bears, there's no way they would tell a complete stranger who's worried about her missing boyfriend about to call the police, Hunting bears in Yellowstone, in 2017 would've been illegal. Vinji also said "she states that they walked out of the woods, what if they had killed a bear, were they just going to walk it out of the woods alongside them ?" When Bonny called the Rangers, she told them she was his wife and only his girlfriend. “

The Forrest Fenn Treasure Hunt

Family members have confirmed that when he died, Mike Petersen was searching for the treasure chest hidden by a millionaire and retired Santa Fe, New Mexico art dealer, Forrest Fenn. The chest was filled with antique coins and relics, a jar of Alaskan gold dust, and an ancient Chinese jade carving by Fenn, buried somewhere in the wilderness. Several people were killed in the wilderness trying to find Fenn's treasure box, and it seems Petersen is one of these unlucky individuals.

Fenn hid the treasure after a 1988 terminal cancer diagnosis, which later went into remission. He subsequently wrote a self-published book in 2010 called “The Thrill of the Hunt,” which contained a short poem describing the treasure’s location in the Rocky Mountains between the Canadian border and Sante Fe above 5,000 feet.

Fenn spent several summers fly fishing in Yellowstone and lived in West Yellowstone in Montana. The poem has phrases that seem to match places in Yellowstone, including "warm waters halt," "canyon down," and "home of Brown" bears.

As I have gone alone in there
And with my treasures bold,
I can keep my secret where,
And hint of riches new and old.

Begin it where warm waters halt
And take it in the canyon down,
Not far, but too far to walk.
Put in below the home of Brown.

From there it’s no place for the meek,
The end is drawing ever nigh;
There’ll be no paddle up your creek,
Just heavy loads and water high.

If you’ve been wise and found the blaze,
Look quickly down, your quest to cease
But tarry scant with marvel gaze,
Just take the chest and go in peace.

So why is it that I must go
And leave my trove for all to seek?
The answers I already know
I’ve done it tired, and now I’m weak

So hear me all and listen good,
Your effort will be worth the cold.
If you are brave and in the wood
I give you title to the gold.

In 2013, Fenn gave The Today Show four more clues: The treasure is hidden higher than 5,000 feet above sea level, it is not associated with any structure nor in a graveyard and not hidden in Idaho or Utah. On July 12 2015, Fenn gave a new clue on the TV show Sunday Morning. "The treasure is not hidden in a mine. A lot of these old mines are dangerous. I mean they have snakes in them, they have black widow spiders.”

On June 6, 2020, Fenn posted on the searcher blog "Thrill of the Chase" that the treasure had been found.

"It was under a canopy of stars in the lush, forested vegetation of the Rocky Mountains and had not moved from the spot where I hid it more than 10 years ago. I do not know the person who found it, but the poem in my book led him to the precise spot. I congratulate the thousands of people who participated in the search and hope they will continue to be drawn by the promise of other discoveries. So the search is over. Look for more information and photos in the coming days."

This was subsequently confirmed via email by Fenn, who further disclosed in a news article that the finder was a male from the eastern United States who had sent him a photograph. The identity of the finder, the photograph, and the location of the treasure were not revealed.

On June 16, 2020, Fenn released additional photos on “The Thrill of the Chase” blog site including of himself examining the contents of the chest and one of it sitting in weathered condition implicitly on or near the site where it was found. On July 22 Fenn stated on the blog site that the treasure's finder had authorized him to disclose, in the interests of closure for many of its searchers, that it had been hidden in Wyoming.

In December 2020, Jack Stuef, a medical student from Michigan, revealed that he found Fenn's treasure chest and decided to disclose his identity by going public in an interview with Outside. Due to safety reasons, he preferred to stay anonymous but a lawsuit was expected to reveal his identity.

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