Lisa Mills immediately knew her daughter was dead when the sheriff called her on a dark November evening.

“The sheriff called us, and they wouldn’t tell us what was wrong but they said they had to come to our house,” Mills said. “And that’s when I knew. They don’t come to your house unless someone has died. So I told my husband that Linnea died, and we need to prepare ourselves.”

Scott and Lisa Mills had to wait until after midnight for the Flathead County sheriff to tell them Linnea had drowned in Lake MacDonald in Glacier National Park while attending open-water scuba training taught by Gull Dive of Missoula. They also learned the National Park Service was investigating the incident, because Gull Dive did not have a commercial-use authorization to operate in the park.

Now, six months later, the investigation is still ongoing, but parts of it are included in an 112-page lawsuit the Mills and two other divers filed this week against Gull Dive, its owners David and Jeannine Olson, and dive instructors Debbie Snow and Seth Liston.

The lawsuit also accuses the Professional Association of Diving Instructors Worldwide Incorporation of being negligent in its oversight of its member businesses.

The details mentioned below are all from the complaint filed in Missoula County District Court this week.

Lake McDonald at dawn, Glacier National Park. (Sherry Devlin/Missoula Current file)
Lake McDonald at dawn, Glacier National Park. (Sherry Devlin/Missoula Current file)

Linnea Mills was an 18-year-old who had discovered the joys of scuba diving a few years earlier while helping with marine biology projects with the University of North Carolina.

Having attained her PADI Open Water certification after four dives, she did a dive on the Great Barrier Reef in 2018.

Before last year, all Linnea’s dives had been in warm and relatively shallow water. But to get her advanced open water certification for a new opportunity, Linnea enrolled in October with Gull Dive, which trains students in Montana’s colder mountain lakes.

Linnea rented equipment and a wetsuit from Gull Dive for her first dive in Seeley Lake but received no orientation or instruction as required by PADI. When they got to the snowy lake, it was below freezing. One student decided not to dive and gave Linnea a second wetsuit, so she could stay warm.

Still, Linnea was thrilled, writing that night in her journal, “That drive back (I) felt this exhilaration of energy like everything is here. It’s all here. We made it. Life begins here. Let’s manifest more.”

Lisa said Linnea kept a detailed journal.

“She was super careful and thorough. She kept a journal and she was so meticulous. We knew she was looking to them. Whatever they said to do, she was doing it,” Lisa told the Missoula Current on Friday.

But instructor Seth Liston had almost less experience than Linnea, and Debbie Snow was a newly certified instructor who wasn’t certified to teach diving at altitude or diving with a dry suit, both of which present dangers. Divers have to use more air in order to remain buoyant at higher altitudes. If they’re used to diving at sea level, they’ll sink more.

Because the next dive on Nov. 1 was to be in MacDonald Lake, the instructors told Linnea and another student, Nathan Dudden, they should wear dry suits and suggested they buy suits from Kendra Potter.

Dry suits keep divers warm by maintaining an envelope of air around the diver. But in a descent, water pressure increases, so divers need to add more air in their suits to compensate for the pressure. Divers need to be properly trained or the pressure can push in on the diver, changing their buoyancy and squeezing the suit around them, restricting their movements.

Linnea bought a used custom dry suit but didn’t receive a special hose and connection needed to inflate the suit. Having never used a dry suit, Linnea wasn’t aware it was missing, and the Gull Dive instructors didn’t check or reconfigure her gear prior to the drive up to Lake MacDonald.

Linnea Mills and Scott Mills during high school graduation.
Linnea Mills and Scott Mills during high school graduation.

The group got to the lake late at 4 p.m., with light already fading. Lake MacDonald Lodge had closed for the season the previous day. Two students, Bob Gentry and 14-year-old E.G., were waiting for them, having completed their dry suit training a month earlier.

The instructors then discovered the air tank regulator they rented to Linnea couldn’t be connected to her dry suit. Instead of cancelling the dive, the instructors told Linnea she could use her inflatable buoyancy control device, or BCD, to keep herself vertically in position.

But Linnea’s control device was for use with her wetsuit, not a heavier dry suit. Also instead of a quick-release weight belt,  the instructor put 44 pounds of lead weights in the pockets of Linnea’s dry suit and BCD.

The students entered the water at 5 p.m. without receiving any safety briefings. Snow took Linnea and E.G. down to 15 feet for about 5 minutes, during which E.G. was cold, fearful and struggling. Snow took E.G. out of the water, not noticing Linnea or the fact that all the air had been squeezed out of her dry suit.

A few minutes later, Snow and Liston took Linnea, Gentry and another student down to 60 feet. Gentry had a diving light and wore a GoPro on his chest, so Linnea’s plight was recorded.

Five minutes into the dive, Linnea was standing on an underwater ledge, struggling to breath or move, because the water pressure at 60 feet was double that at the surface. She tried to kick to the surface but couldn’t overcome the weights and lack of buoyancy that held her down. Swimming nearby, Snow didn’t look at Linnea.

Linnea frantically signaled to Gentry, who immediately swam to help. But Linnea’s gestures spun her backward, and she rapidly sank, her eyes wide with fear as she reached for Gentry. Gentry swam after her, finally catching her at a depth of 85 feet, where the water pressure is three times that at the surface. Linnea struggled to breathe as the dry suit sucked around her body, crushing her.

Gentry worked for 32 seconds trying to save Linnea as they continued to sink, but he couldn’t find the lead weights to drop them. As Linnea lost her air regulator, Gentry tried to give her air from his. But with the higher pressure, they were both quickly running out of air. As a last effort, Gentry tried to heave Linnea upward but couldn’t lift her.

Finally, he went for help, rocketing from 105 feet deep to the lake surface in less than a minute, a dangerous ascent. At first, Gentry couldn’t locate anyone, but Snow eventually surfaced. Hearing Gentry’s story, she dove briefly to look for Linnea but couldn’t find her. On a second dive, they finally found Linnea at 127 feet and returned her lifeless body to the surface.

After Snow and Liston were airlifted to Seattle, Wash., Jeannine Olson in Missoula allegedly told the coroner that Linnea was “witnessed by a dive buddy to panic, then fall passively to the bottom of a lake after swimming without difficulty at a depth of approximately 40 feet.”

As a result, the medical examiner didn’t note the bruising on Linnea’s body caused by the dry suit squeeze and other issues caused by the high pressure. Jeannine also allegedly called Gentry later to say he was responsible for Linnea’s death.

The Mills have subsequently become friends with Gentry and invited him to Linnea’s memorial.

“We haven’t had a chance to thank him publicly. We want to publicly acknowledge what he did. He’s quite affected by what happened, and he’s such a sweet man,” Lisa said. “It’s devastating the more we learn. There are three of us in the family, and we each handle things differently. But every time evidence is brought forward, you’re like ‘whoa.’ It just kind of hits you like another hard wave.

One of the Mills’ attorneys, David Concannon of Sun Valley, Idaho, has worked on many cases related to scuba diving. Lisa said Concannon said he’d never seen such an egregious case.

Concannon is holding PADI responsible, arguing that PADI prides itself in its programs and merchandise but doesn’t hold the members of its Retailer and Resort Association accountable. Instead, RRA members get incentives to sell more certifications and employ more instructors, which can lead some to cut corners and take chances. If shops break the rules, PADI doesn’t inform the public if a shop is expelled from the organization.

In Linnea’s case, the Gull Dive instructors weren’t fully qualified and failed to follow a myriad of safety practices and guidelines touted by PADI. But it’s not the first time Gull Dive has broken rules.

Last July, according to records, Ellen Hubbell sued Gull Dive in the death of her husband Jesse who drowned in Canyon Ferry in June 2019. Jesse hadn’t scuba dived in more than 25 years so he wasn’t certified, but Gull Dive still rented equipment to him and it was later found Hubbell’s regulator was on backward.

The Hubbell case is still ongoing but hadn’t gotten far by the time Linnea started interacting with Gull Dive. But there was no way for students like Linnea to know about the Hubbell case because Gull Dive didn’t report it to PADI in 2019 and kept using the PADI name.

In the meantime, the lawsuit alleges the Olson’s have siphoned corporate funds from Gull Dive.

The Mill’s and Gentry’s are suing for $12 million.

“For us, it’s all about getting to the entire truth, having it known publicly. Because ultimately, we think we could save other lives. Otherwise, this would be almost too much. If there wasn’t a chance, why would we go through this? But we think this is going to inform the scuba industry,” Lisa told the Current.

Contact reporter Laura Lundquist at