Background: The Scuba Ranch training lake in Terrell, Texas (KDFW). Inset (left): William Armstrong (Kaufman County Sheriff”s Office). Inset (right): Dylan Harrison (lawsuit).
After a Texas family filed a lawsuit against two scuba companies following the drowning death of their 12-year-old daughter, an arrest has been made.
William Armstrong, a former assistant chief deputy in Collin County, has been charged with felony injury to a child. Armstrong was the certified scuba instructor tasked with supervising 12-year-old Dylan Harrison during a diving certification class on Aug. 16, 2025, along with certified divemaster Jonathan Roussel. At some point during the class, Dylan disappeared. More than 30 minutes after her instructors noticed she was gone, she was found unresponsive and was pronounced dead by emergency medical personnel.
As Law&Crime previously reported, Dylan’s family sued Armstrong, Roussel, the National Association of Underwater Instructors that issued their respective certifications, and other organizations connected with the scuba class Dylan was taking. The Harrisons booked the class and bought equipment at Scubatoys in Carrollton, Texas, which also hosted an introductory class before the eight students and two instructors headed to a lake at The Scuba Ranch.
Scubatoys and The Scuba Ranch are also listed as defendants in the lawsuit.
In Armstrong’s case, the lawsuit stated that in addition to his full-time job at the Collin County Sheriff’s Office, he worked as a security guard. The lawsuit said that the day before Dylan’s class, Armstrong worked a full daytime shift as well as a full overnight shift at his second job. By the time he got to the class, he had “little or no sleep in the past 24 hours.”
According to the lawsuit, once Armstrong and Roussel realized that Dylan had become separated from her classmates, Roussel brought the other students to shore while Armstrong searched on land. Emergency personnel were also called, and “additional divers and personnel at the Scuba Ranch” arrived to aid in the search.
However, “Armstrong and Roussel were seen leaving the area and, when they returned, they were reportedly unhelpful in guiding the search for [Dylan]. Consequently, the initial search was disorganized and inefficient, wasting valuable time.”
Local Fox affiliate KDFW reported that Armstrong resigned from his position at the Collin County Sheriff’s Office in October. Scubatoys closed its doors on Jan. 31.
Armstrong was charged with felony injury to a child on Friday. After he was booked into the Kaufman County Jail, he posted a $150,000 bond and was released. His next court date was not available.
Conrad Hoyt contributed to this report.
