NEW: Coast Guard releases footage of OceanGate CEO Stockton Rush's wife unknowingly reacting to the death of her husband, who was crumpled alive in the Titan submersible.

"What's that bang?" Wendy Rush was heard asking.

According to the Coast Guard's investigation, the Titan's carbon fiber shell started breaking apart during a previous mission to the Titanic.

The carbon fiber began "separating into layers," which is a process called delamination.

"Delamination at dive 80 was the beginning of the end," said US Coast Guard Lt. Cmdr. Katie Williams. "Everyone that stepped onboard the Titan after dive 80 was risking their life."

Clothing belonging to Rush was found in the wreckage, including business cards.