Texas child's dive death raises serious questions

An investigation is underway after the unexplained death of 12-year-old dive trainee Dylan Harrison, who passed away after a 'miscommunication between a student and the instructor' on a scuba training course in Terrell, Texas.

Dylan was hoping to secure her open-water certification at the privately-owned Scuba Ranch on August 16, 2025, but went missing on the dive. She was one of eight students accompanied by diving instructor Armstrong and Dive Master Jonathan Roussel.

In early October it was revealed that Armstrong, who at the time was a part-time dive instructor alongside his day job as the Assistant Chief Deputy for Collin County Sheriff's office in McKinney, Texas, had worked solidly through the previous day and night. The Sheriff's office confirmed he worked his day job on Friday, 15th August, before going to a second job as a private security guard in the town of Plano from 9pm to 6pm. He finished that job just two hours before he was due to take the open-water certification class in Terrell, an hour's drive from Plano.

Despite having had no sleep, Armstrong and the group descended to a five-metre deep platform in poor visibility. The group resurfaced, but according to at least one of the other trainees, the second descent wasn't coordinated, and this is when Dylan went missing. Her absence wasn't noticed until a later headcount, and no immediate search appears to have been launched. 

While Armstrong and Roussel say the divers filed down a descent line, another student on the course has alleged everyone descended at once. Once back at the platform, a headcount revealed Dylan was missing. The Dallas County Sheriff's office dive team, who had been training at the lake, launched a search and found her at a depth of about 13 metres, some way from the platform. 

The investigation is focused on several issues, including an apparently delayed response to a diving emergency, and buddying-up of two 12-year-old trainees in poor visibility. Officers also failed to retrieve and analyse data from the dive computers worn by Dylan, her instructor, the dive master and one of the other trainees in the group, according to a US news report. The unit belonging to one of the two dive professionals present is since said to have been lost in a 27m-deep lake.

"This is the first case I've had where answers have not been forthcoming, and evidence wasn't gathered at the scene or shortly thereafter, by the people who know what to do," says lawyer and diver David Concannon, who is providing his services pro bono to Dylan's family. He likened the failure to consider dive computer data to ignoring the black box after a plane crash.