The US Coast Guard said on Sunday it had launched an investigation into the cause of the underwater implosion that destroyed the small submersible Titan, with the loss of all five people aboard, including two Pakistanis, during a dive to the Titanic wreck.

On board the craft were Engro Corp Vice Chairman Shahzada Dawood and his 19-year-old son Suleman, British explorer Hamish Harding, French submarine expert Paul-Henri Nargeolet, and Stockton Rush, US founder and chief executive officer of OceanGate Expeditions, which operated the submersible and charged $250,000 per person to make the Titanic trip.

The Coast Guard said it had created a marine board of investigation (MBI), its highest level of probe, for this drama and ultimately tragedy in the North Atlantic that drew worldwide attention.

“My primary goal is to prevent a similar occurrence by making the necessary recommendations to enhance the safety of the maritime domain worldwide,” Jason Neubauer, the Coast Guard’s chief investigator and leader of this probe, told a press conference in Boston.

“The MBI is already in its initial evidence-collection phase, including debris salvage operations at the incident site,” he added.

Neubauer said the US probe could also make recommendations on the possible pursuit of civil or criminal sanctions “as necessary”.

Titan was reported missing last Sunday and the Coast Guard said on Thursday that all five people aboard the submersible had died after the vessel suffered a catastrophic implosion.

A debris field was found on the seafloor, 500 metres from the bow of the Titanic, which sits nearly four kilometers below the ocean’s surface and 400 miles off the coast of Newfoundland, Canada.

Canada, which helped in the search for the submersible, said on Saturday it was carrying out its own probe.

The Canadian-flagged Polar Prince cargo vessel towed the Titan out to sea last weekend but lost contact with it about an hour and 45 minutes after the submersible launched into the ocean depths.

The announcement of the implosion ended a multinational search-and-rescue operation that captured the world’s attention since the tourist craft went missing.