One of the co-founders of the firm behind the missing Titanic submersible fears there was an "instantaneous implosion" of the craft that CEO Stockton Rush was piloting with four passengers.
It comes as the US Coast Guard announced that a "debris field" has been found within the search area near the Titanic wreck.
Guillermo Söhnlein, who co-founded OceanGate with Stockton Rush, explained that their protocol for lost communications is for the pilot to surface the sub.