US Coast Guard investigating cause of Titanic submersible implosion

FILE PHOTO: The Titan submersible, operated by OceanGate Expeditions to explore the wreckage of the sunken SS Titanic off the coast of Newfoundland, dives in an undated photograph. OceanGate Expeditions/Handout via REUTERS/File Photo

(Reuters) -The U.S. Coast Guard is investigating the cause of the undersea implosion of a tourist submersible that killed all five people aboard while diving to the century-old wreck of the Titanic, officials said on Sunday.

The announcement comes a day after Canada's Transportation Safety Board said it was conducting its own investigation into the implosion of the Titan, which has raised questions about the unregulated nature of such expeditions.