How to Kill a Mermaid

An emotional new film made a big impression at Montana's Big Sky Documentary Film Festival in early March. It was How to Kill a Mermaid: The Linnea Mills Story, directed and produced by a friend of the Mills family, Damon Ristau.

Previously in Undercurrent, we've extensively covered how the 18-year-old died in 2020 during what was meant to be a PADI Advanced Open Water Diver (AOD) course in Lake MacDonald in Montana's Glacier National Park. A wrongful death lawsuit followed, which was settled out of court. Fellow trainee Bob Gentry and Mills's parents sought up to $12 million in damages for alleged negligence, unsafe diving practices, and training violations by Gull Dive Center of Missoula, its instructor Debbie Snow, volunteer dive assistant Seth Liston, and PADI.

The claims never went before a jury, and no admission of guilt by anyone was ever made.

The events, laid out by this well-made but disturbing documentary, will make any diver alarmed or even squirm with anger, as it reveals new evidence. Some would say that a minimum charge of negligent homicide was possible for this tragic and entirely unnecessary death, but it appears that those involved went away with nothing more than a metaphorical slap on the wrist.

A tribute to the modern habit of recording all family events on smartphones, the film production includes both a rich archive of home-movie material establishing that Linnea Mills was an adventurous teen and happy to be outdoors, as well as crucial GoPro footage obtained at the time of the tragedy by fellow trainee Bob Gentry. It uses his camera footage as an eyewitness.

That said, the use of a camera during training by a trainee is, itself, a breach of PADI standards in that no trainee should be so distracted by such an activity during a course, but instructor Snow appeared to be unaware of that.

Linnea had dived in the tropical waters of the Great Barrier Reef three years earlier, but decided to rekindle her interest in scuba diving and marine biology. She was persuaded, after an interaction on social media, by Debbie Snow, a recently qualified PADI instructor and local hairdresser, to embark on further education with Missoula's Gull Dive Center.

After an initial unpleasant and aborted foray into the icy waters of Montana in a wetsuit, Mills realized she needed a drysuit and bought one second-hand. Unbeknownst to her, this suit was missing an essential ingredient -- its direct-feed hose. Mills did no pool training with the suit before the fateful trip to the lake.

One November day, Snow, who appeared to have little previous experience of cold water diving, decided to combine an AOD course with a drysuit specialty course in the glacial lake. The location was a long drive from the dive center, and preparation before the dive was shown to be chaotic: one of the dive center's Imperial-fitting direct-feed hoses could fit the metric connection to Mills's drysuit, so Snow told her to dive without that crucial drysuit inflation.

At the same time, the BC supplied for Mills by Gull Dive Center was missing its quick-release weight pockets -- so Snow loaded up Mills' BC accessory pockets and the pocket of her drysuit instead with an inordinate amount of lead (44 pounds) for such a slightly built girl. Perhaps the instructor felt it was needed to get the nervous-with-trepidation teenager to submerge. It was dusk before the divers finally got into the water.

The documentary is interlaced with the haunting surface beauty of the Montana lake, itself closed to the public for winter at the time, incidentally demonstrating its remoteness from any emergency help. At 3,500- feet altitude, the lake is deep-sided and icy cold -- consequently unsuitable for dive training. Furthermore, Gull Dive Center was not licensed by the Park Service to operate in that lake.

Bob Gentry's own underwater footage, obtained at the time, reveals the instructor Snow swimming about underwater, barely in control of her own buoyancy. Meanwhile, Linnea Mills plunged deeper and deeper, unnoticed by the instructor in whom she had entrusted her safety, but caught by the camera.

Suit Squeeze

It appears that Mills was strangled by the neck seal of her suit, as the increasing water pressure on the material could not be alleviated by any direct-feed air into the suit as she went deeper.

Bob Gentry saw she was in trouble in some way and tried to rescue her in the gloomy depths, but was unsuccessful. He abandoned the attempt by the time they dropped together to 140 feet deep. Snow continued to go about the dive, seemingly oblivious to what was happening. It was getting dark, and Mills was not equipped with a light. One error followed another. The teenager died.

Back at the surface, Gentry told Snow what happened to Mills, and in the ensuing panic to search for her, Snow's assistant Seth Liston's drysuit became over-inflated, sending him hurtling to the surface suffering a gas embolism. Snow recovered Mills' body.

After the tragic event, there followed a further litany of errors, with inadequacies and ignorance by the investigating authorities. Snow had taken the dive computer from the deceased's wrist and had kept it in her possession, and the National Park Service investigators failed to understand the computer's importance even when she admitted to having it during a following interview. Whether by ignorance or deception, she wrongly told the investigators that Mills' computer had no facility for downloading, and the only information available was what was showing on its screen.

The documentary details the repercussions that followed for those involved. Trainee Bob Gentry was blamed by the diving professionals, including the dive center's owners, for his inadequate rescue attempts, despite his valiant actions. He felt he was blamed for the death of someone he didn't know, and was only paired with her as a matter of convenience. He fears he might end up in prison. His GoPro footage, obtained despite being against PADI standards for a trainee, is telling.

The tragedy also later reveals irreparable fractures in the marriage of Linnea Mills' parents.

The eyewitness accounts of what had happened punctuate the narrative, augmented by scathing opinions from experienced diving lawyer David Concannon, and veteran FBI investigator Mike Pizzio (formerly of the Bureau's dive team).

However, there is finally a layer of optimism in the film when it is revealed that Mills' brother Nick later decides he wants to learn to dive, to "become the sort of diver who might have been able to save his sister." He goes on to embark on a career in diving.

At 135 minutes, it may seem a little long for a documentary, but divers will find it thought-provoking.

In light of the recent and equally tragic death of 12-year-old Dylan Harrison during a training dive in a Texas lake, the timing of the documentary is even more prescient. It brings into question the unregulated manner of dive training in the USA. An out-of-court settlement won't make this one go away, and PADI will not welcome this film.

It's an important production, and we indeed hope it becomes available through an Internet streaming service.

John Bantin