The around-the-clock search for the missing Titan submersible engrossed the world for days. But after news of the catastrophic implosion that killed the pilot and his four passengers near the Titanic shipwreck, investigators are focusing on how it happened — and if it could have been prevented. Deep-sea robots continue searching the North Atlantic ocean floor for clues. Investigators in Canada are looking at the Titan’s Canadian-flagged support ship. U.S. authorities are looking into other aspects of the tragedy. The Titan, owned by undersea exploration company OceanGate Expeditions, had been chronicling the Titanic’s decay and the underwater ecosystem around the sunken ocean liner in yearly voyages since 2021.