Instructor resigns from Collin County Sheriff's Office following 12-year-old’s scuba death

TERRELL, Texas - There has been an update on FOX 4's investigation into the death of Dylan Harrison during her scuba class. 

FOX 4 has learned that the instructor, an assistant chief deputy with the Collin County Sheriff's Office, resigned last week.

Instructor's resignation

What we know:

This morning, Sheriff Jim Skinner confirmed that Assistant Chief Deputy William Armstrong, Dylan's instructor, offered his resignation on Tuesday, effective immediately.

The resignation of assistant Chief William Armstrong came less than a week after FOX 4 first reported on the death of his scuba class student, 12-year-old Dylan Harrison.

Investigation and 'lost' evidence

The backstory:

Harrison was an active girl, enjoying everything from archery to aerial skills and gymnastics. Experts tell us getting her scuba certification should never have cut her life short. She was seen getting in the water with a 12-year-old boy as a buddy on August 16.

As reported on October 15, what happened next is still a mystery for her family.

Dylan Harrison and the incident

What they're saying:

David Concannon, an attorney helping the Harrisons to get answers, told FOX 4 that is due in large part to evidence that should have been readily available from Armstrong's dive computer, and that of the dive master, Jonathan Roussel. 

"That's a black box that'll show you a tremendous amount of information about what happened to Dylan," said Concannon.

An email from an investigator to Concannon said the investigator has been in contact with the dive master, and dive instructor, Armstrong, and "No data is to be recovered." 

"It's unusual. That so many people who know what to do were present, and things that weren't done," he stated.

After our first report, a witness came forward with information he tried to give to the Kaufman County Sheriff's Office, but he was told the investigation was closed. 

"I asked, ‘Who is the instructor here? Is there a professional here?’ No one answered. A lady walked down I said, ‘Is there an instructor here?’ She said, ‘Yes, my husband.’ I said, ‘Where is he?’ She said, ‘He's standing right in front of you.’"

Witness claims investigation was rushed

Dig deeper:

Experts say a scuba instructor should always be the first one in and the last one out. 

"He started telling me I didn't do anything wrong," said ___ . "He was bone dry."

Dylan's parents received a phone call 97 minutes after Dylan was pronounced dead that her case was marked closed. The Kaufman County Sheriff's Office now says the case is still an open investigation. 

The scuba ranch told FOX 4 that immediately after Dylan’s death, Armstrong was permanently suspended from teaching at the facility. One of Armstrong’s roles at the Collin County Sheriff's Office was to oversee professional standards.  

The sheriff's office did not have any written documentation that he provided notice that he was part of an open criminal investigation involving Dylan’s death, but Sheriff Skinner told FOX 4’s Lori Brown by phone that Armstrong told him in a phone call that day. 

Crime and Public SafetyCollin CountyKaufman CountyTerrell