Rockwall family thanks Texas Rangers after scuba instructor arrested in connection to death of 12-year-old at North Texas dive facility

A Rockwall family is grateful for the Texas Rangers after they arrested a scuba instructor for alleged negligence that led to the death of their 12-year-old daughter. 

The death of 12-year-old Dylan Harrison happened 6 months ago. Her father is still emotional talking about it.

While the parents did not want to go on camera, they sent a statement about the arrest of a scuba instructor, a former Collin County Sheriff's deputy, in connection with the child's death. 

Photos from the last day of Dylan Harrison's life show who she was: an adventurous, bright and beautiful 12-year-old who wanted to learn how to scuba dive. 

Her family says she enrolled in a program at The Scuba Ranch in Terrell last summer. 

On Aug. 16, Dylan and seven other students were in the water for a buoyancy test, wearing scuba gear. 

A civil lawsuit filed by the family says that instead of floating, Dylan sank to the bottom of the pond due to the weight, while instructors were not paying attention. 

Her body was found 30 minutes later at a depth of 45 feet. 

The lawsuit contends that, based on the air in her tank, Dylan "was alive and breathing off her tank for several minutes after she was last seen [sic]. During this time, D.H. was alone, in poor visibility, and unable to reach the surface."

One of the instructors, identified as William Armstrong, was also a Collin County Sheriff's deputy at the time. He was arrested earlier this month and charged with injury to a child after an investigation by the Texas Rangers. 

The family's lawsuit accuses Armstrong and others of leaving the area after conducting only a brief search, while it took first responders only 7 minutes to find and remove Dylan from the water. 

By that time, it was too late. 

In a statement to CBS News Texas, Dylan's parents said:

"We are forever grateful to the Texas Rangers for stepping in and working hard to not only obtain justice for our daughter, and hopefully protect others in the future. We cannot thank you enough for your tireless dedication to seeking the truth. Dylan's death was senseless and beyond tragic."

Armstrong resigned while suspended from the Collin County Sheriff's office. 

The just-released arrest report says Armstrong lied about being in the water until rescue crews arrived, and on the day of Dylan's death, the report says he was near the end of working 29 hours straight at his three back-to-back jobs.