How to Kill a Mermaid: The Linnea Mills Story Examines a Scuba Training Tragedy 

A tragic entry in true-crime documentaries, The Linnea Mills Story details the harrowing 2020 death of an 18-year-old during a cold-water scuba training session in Glacier National Park, Montana. Featuring previously unreleased footage, the film re-evaluates the circumstances surrounding the fatal incident and the subsequent inquiry. It offers a poignant look at a life ended far too soon, chronicling her family’s steadfast fight for truth, justice, and accountability amid deep personal grief.

The wrongful-death civil action initiated by her parents, alongside fellow trainee Bob Gentry and additional plaintiffs, pursued up to $12 million in compensation. The suit cited claims of negligence, hazardous procedures, and training breaches against scuba instructor Debbie Snow and volunteer assistant Seth Liston, their employer Missoula-based Gull Dive, company owners David and Jeannine Olson, and the certifying organization PADI.

The civil action and subsequent investigations detailed an extensive breakdown of standard safety protocols and industry mandates surrounding the incident. Linnea, an inexperienced diver enrolled in an Advanced Open Water class, had explicitly informed staff at Gull Dive that she had no prior training with drysuits. Rather than providing the required instructional preparation or turning her away, employees circumvented PADI policies—which restrict drysuit rentals to certified individuals—by facilitating a private sale of a used suit directly to her. This secondhand gear proved dangerously defective, as it featured an incompatible inflation connection that prevented Linnea from hooking up her air supply. As a result, she was unable to inject air into the suit during her descent, suffering severe “suit squeeze” that violently compressed her torso.

The physical hazards were compounded by critical operational errors on land and in the water. Linnea was over-weighted with approximately 44 pounds of lead ballast packed into pockets rather than attached to a quick-release belt, leaving both her and her fellow divers incapable of shedding the weight when she began to sink. Lead instructor Debbie Snow lacked the credentials to teach drysuit diving and had never previously dived at Lake McDonald, yet the team skipped both pool orientations and routine pre-dive gear checks that would have exposed the missing inflator connection. To make matters worse, the excursion was launched late in the afternoon with inadequate lighting gear, at a location that had already been closed for the winter season by the National Park Service, and without the mandatory commercial permits required to conduct training there.

Following the incident, the diving industry and the business owners enacted significant administrative changes. In early 2023, PADI officially revoked instructor Debbie Snow’s membership, permanently expelling her from the organization. Meanwhile, Gull Dive Center ceased operations entirely after its owners, David and Jeannine Olson, formally dissolved the business entity in 2022.

How to Kill a Mermaid: The Linnea Mills Story is being screened at film festivals during 2026, bringing Linnea’s story and the questions surrounding her death to a new audience.