Two weeks of public testimony concluded Friday in the U.S. Coast Guard’s investigation to establish what caused the Titan submersible to implode during a deep ocean dive last year, killing all five on board.

Its findings will be issued in a report that may include what the panel believes caused the incident; whether there was any act of misconduct, negligence or violation of law; and safety recommendations that could prevent future calamities involving submersibles.

The hearing in South…