The Polar Prince arrives on Saturday at the port in St. John’s, Newfoundland. Authorities from the U.S. and Canada began the process of investigating the cause of the fatal Titan submersible implosion even as they grappled with questions of who was responsible for determining how the tragedy unfolded. Adrian Wyld /The Canadian Press via Associated Press

The Transportation Safety Board of Canada said Saturday that it’s conducting an investigation into the loss of the Titan submersible and has been speaking with those who traveled on Titan’s mothership, the Polar Prince.

The development comes as authorities from the U.S. and Canada began the process of probing the cause of the underwater implosion and grappled with questions of who was responsible for determining how the tragedy unfolded.

Maritime agencies are searching the area in the North Atlantic where the vessel was destroyed, killing all five people aboard. Debris was located about 12,500 feet underwater, several hundred feet away from the Titanic wreckage it was on its way to explore.

“We are conducting a safety investigation in Canada given that this was a Canadian-flagged vessel that departed a Canadian port and was involved in this occurrence, albeit in international waters,” said Kathy Fox, chair of the transportation board. “Other agencies may choose to conduct investigations and that’s up to them.”

The Polar Prince left Newfoundland on June 16, towing the ill-fated Titan. There were 41 people on board – 17 crew members and 24 others – including the five who died when Titan imploded.

Fox said she understands the international interest and that the TSB will share information they collect with other agencies, like the U.S. National Transportation Safety Board and the U.S. Coast Guard, within the limits of Canadian law. Voice recordings and witness statements are protected under Canadian law, she said.

“Our investigation will go where the evidence leads us,” she added. “We don’t want to duplicate efforts. We want to collaborate.”

The Royal Canadian Mounted Police also announced Saturday that they’ve initiated an examination of the circumstances that led to the Titan deaths to decide whether a full investigation is warranted. That full probe will only take place if it appears criminal, federal, or provincial law may have been broken, officials said.

The Coast Guard led the initial search and rescue mission, a massive international effort that likely cost millions of dollars.

It was not entirely clear who would have the authority to lead what is sure to be a complex investigation involving several countries. OceanGate Expeditions, the company that owned and operated the Titan, is based in the U.S. but the submersible was registered in the Bahamas. OceanGate is based in Everett, Washington, but closed when the Titan was found. Meanwhile, the Titan’s mother ship, the Polar Prince, was from Canada, and those killed were from England, Pakistan, France, and the U.S.

The National Transportation Safety Board said Friday that the U.S. Coast Guard has declared the loss of the Titan submersible to be a “major marine casualty” and the Coast Guard will lead the investigation.

The Coast Guard has not confirmed that it will take the lead.

The deep-sea investigations promise to be long and painstaking, given the murky depths of the ocean.

“This is an incredibly unforgiving environment down there on the seafloor,” said Rear Adm. John Mauger, of the Coast Guard First District.

How the overall investigation will proceed is complicated by the fact that the world of deep-sea exploration is not well-regulated.

A key part of any investigation is likely to be the Titan itself. Questions have been raised about whether the vessel was destined for disaster because of its unconventional design and its creator’s refusal to submit to independent checks that are standard in the industry

The Titan was not registered as a U.S. vessel or with international agencies that regulate safety. And it wasn’t classified by a maritime industry group that sets standards on matters such as hull construction.

OceanGate CEO Stockton Rush, who was piloting the Titan when it imploded, complained that regulations can stifle progress.

“Bringing an outside entity up to speed on every innovation before it is put into real-world testing is anathema to rapid innovation,” Rush wrote in a blog post on his company’s website.

One question that seems at least partially resolved is when the implosion likely happened. After the Titan was reported missing, the Navy went back and analyzed its acoustic data and found an “anomaly” Sunday that was consistent with an implosion or explosion in the general vicinity of where the vessel was operating when communications were lost, said a senior U.S. Navy official.

The Navy passed on the information to the Coast Guard, which continued its search because the data was not considered definitive, according to the official, who spoke on condition of anonymity to discuss a sensitive acoustic detection system.

The Titan launched at 8 a.m. that day and was reported overdue that afternoon about 435 miles south of St. John’s, Newfoundland. Rescuers rushed ships, planes, and other equipment to the area.

Any sliver of hope that remained for finding the crew alive was wiped away early Thursday when the Coast Guard announced that debris had been found near the Titanic.

Killed in the implosion were Rush, two members of a prominent Pakistani family, Shahzada Dawood and his son Suleman Dawood; British adventurer Hamish Harding; and Titanic expert Paul-Henri Nargeolet.

A flurry of lawsuits is expected, but filing them will be complex and it’s unclear how successful they will be. Plaintiffs will run into the problem of establishing jurisdiction.

At least 46 people successfully traveled on OceanGate’s submersible to the Titanic wreck site in 2021 and 2022, according to letters the company filed with a U.S. District Court in Norfolk, Virginia, that oversees matters involving the Titanic shipwreck.

But questions about the submersible’s safety were raised by both a former company employee and former passengers.

Associated Press writers Lolita C. Baldor in Washington; Ben Finley in Norfolk, Virginia; Holly Ramer in Concord, New Hampshire; David Sharp, in Portland; and Gene Johnson in Seattle contributed to this report.