Fellow student recalls 12-year-old’s scuba death
Ted Sickels is an experienced Caribbean diver who was working to get his U.S. dive certification on the day that 12-year-old Dylan Harrison died. He talked to FOX 4 about what he saw during that deadly class.
DALLAS – For the first time, another student is speaking out about the tragic death of a 12-year-old girl during a scuba diving class in Kaufman County.
Scuba Student’s Witness Account 
What they’re saying:
Ted Sickels has decades of diving experience in the Caribbean. He was in Dylan Harrison’s class on Aug. 16 to get his United States certification.
After giving his initial statement to law enforcement, he provided a more in-depth written statement. Now he’s sharing what he saw with FOX 4.
“He arrived after all the other students had arrived. When he got there it was kind of hurried at that time. He arrived with his wife,” Sickels said.
What he didn’t know at the time was that his scuba instructor, William “Bill” Armstrong, had shown up after working all night.
FOX 4 uncovered that Armstrong arrived to class that morning after working his normal day shift as an assistant chief deputy at the Collin County Sheriff’s Office. Then he worked a second job overnight from 9 p.m. to 6 a.m. at an investment firm in Plano.
The scuba class was scheduled to run from 8 a.m. to 5 p.m.
“His demeanor wasn’t as jolly as it was. He wasn’t joking around as much as he was in the class,” Sickels said.
The class began, and Sickels said for the first submergence, the class used a line from a white buoy to go to a first platform and then a second.
That is standard procedure for first-time open divers like 12-year-old Dylan.
But during submergence, Sickels said he noticed the girl struggling.
“She was not neutral buoyant. She was having to hold onto the rail of the platform. She was not floating like the rest of us,” he said.
Later during that first dive, Sickels said he misunderstood a signal from Armstrong, so he went to the surface.
“He said, ‘Because you came up, I had to bring the entire class up,’” Sickels said.
A photo taken of Dylan when the class surfaced was the last one of her ever taken.
Sickels said Armstrong then instructed the class to descend 15 feet to simulate a three-minute rest stop. But this time it was without the line from the buoy to the platforms.
“He resubmerged the whole entire class as a group,” he said. “They got a head count. The head count was off by one. Bill went back down to see if maybe she was on the platform. And I’m sitting there I’m wondering, ‘Okay, why are you going down there to see if she’s on the platform? We’re not over there on the platform.'”
After the class returned again to the surface, they looked for bubbles with Dive Master Jonathan Roussel.
Sickels said Armstrong came back up and said Dylan was not on the platform.
“He went back down to see if maybe she was under the platform,” he said.
Once again, Armstrong surfaced after an unsuccessful search.
“Told the advanced student I believe it was to use his phone to call and get an ambulance out here,” he said.
Sickels said that’s when Armstrong got out of the water.
“This keeps playing over and over in my head, every night. I’ve probably woke up at least 50 times since that night. It was Bill standing on the dock and Dylan’s mother screaming, ‘Why are you not doing anything? Dylan is afraid when she is alone in the house in a thunderstorm!’ And Bill turned around and looked at her and said, ‘We are doing everything we can. She’s got plenty of air in her tank. As long as she keeps her regulator in her mouth, we will find her, and she will be okay,’” he said.
Sickels said Armstrong then got in a car to go look for help around the lake. That’s something he questioned.
“Where in the hell is he going? He is a certified rescue diver. Why is he not here leading?” he said.
And those aren’t the only questions that replay in his mind. Sickels said if Dylan had simply gone down the line with an instructor or dive master, “none of this would have happened.”
Bill Armstrong’s Resignation 
What we know:
In response to an open records request, FOX 4 has learned that Armstrong submitted two resignation letters to the Collin County Sheriff’s Office.
The first was on Oct. 20 after FOX 4 shared a story with a witness who questioned why Armstrong was out of the water and dry while Dylan was still missing.
That letter said Armstrong planned to retire on Oct. 31.
On the same day, FOX 4 reported that the Texas Rangers were assisting with the investigation.
Armstrong submitted a second letter changing his retirement date to “effective immediately.”
12-year-old Scuba Death 
The backstory:
Dylan drowned on Aug. 16, 2025 during what was supposed to be a happy day. She was set to get her scuba diving certification from Scuba Toys while attending a class at The Scuba Ranch in Terrell. With that certificate, she would be able to join her dad and grandfather scuba diving.
There are lots of questions about what happened next.
According to witness affidavits obtained by the family’s attorney, there were eight students, an instructor, and a dive master in the class.
During the class, Dylan went missing. Her body was later found away from the platform at a depth of about 45 feet, according to the family’s attorney.
The family has questions about why witnesses claimed Armstrong, a Collin County assistant chief deputy, was out of the water and “bone dry” as they began searching for Dylan and why crucial data from dive computers was never collected. One of those dive computers is now lost, according to the attorney.
The Kaufman County Sheriff’s Office confirmed an “open criminal investigation.”
Continued Coverage
The Source: FOX 4’s Lori Brown gathered information in this story by interviewing Ted Sickels, who was in the same class as a 12-year-old dive student who drowned on Aug. 16. Other details are from an open records request and past news coverage.