Investigators search for clues in the deadly implosion of the Titan sub, including voice recorders abord the launch ship that could hold new answers. WATCH FULL EPISODES OF WORLD NEWS TONIGHT: abc.com/shows/world-news-tonight WATCH WORLD NEWS TONIGHT ON HULU: bit.ly/3iQLwPp #Titan #Sub #Implosion #VoiceRecorders #WorldNewsTonight