Canadian authorities said Friday they would launch an investigation into the loss this week of the Titan submersible along with five people onboard during a dive to the Titanic wreck.

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 Canadian Transportation Safety Board said "as the investigation authority of the flag state of the support vessel" it would "conduct a safety investigation regarding the circumstances of this operation."

The US Coast Guard said 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, 1,600 feet (500 meters) from the bow of the Titanic.

The somber announcement ended a multinational search-and-rescue operation that captivated the world since the tiny tourist craft went missing in the North Atlantic four days earlier.

The Transportation Safety Board routinely probes air, rail, marine and pipeline accidents with the aim of improving transportation safety. It does not assign fault or determine civil or criminal liability.

The independent agency said it has sent investigators to St. John's, Newfoundland, from where the Polar Prince set sail, "to gather information, conduct interviews, and assess the occurrence."

"In the coming days, we will coordinate our activities with other agencies involved," it added in a statement.

The Polar Prince is majority owned by the Miawpukek First Nation.

amc/bgs