See photos of recovered Titan sub debris after "catastrophic implosion" during Titanic voyage

Pieces of debris from the sub that officials say imploded while carrying five people to the wreckage of the Titanic last week have arrived back on land. Photos from the Canadian Press and Reuters news agency show crews unloading large pieces of the Titan submersible in Newfoundland.

The debris arrived in St. John's, Newfoundland, Wednesday, the U.S. Coast Guard said in a statement. 

The agency also said "presumed human remains" recovered from the sub's wreckage would undergo analysis by American medical professionals.

Evidence recovered from the sea floor for the U.S.-led investigation into the implosion would be transported to a U.S. port for analysis and testing, the Coast Guard said.

"The evidence will provide investigators from several international jurisdictions with critical insights into the cause of this tragedy," Coast Guard Capt. Jason Neubauer, the chief investigator, said in the statement. "There is still a substantial amount of work to be done to understand the factors that led to the catastrophic loss of the TITAN and help ensure a similar tragedy does not occur again."

The emergence of images of the Titan comes about a week after the Coast Guard announced an underwater robot had discovered debris from the sub about 1,600 feet from the bow of the Titanic at the bottom of the Atlantic. The Coast Guard said the debris was "consistent with a catastrophic implosion of the vessel."

Pakistani businessman Shahzada Dawood, his 19-year-old son Suleman, billionaire adventurer Hamish Harding, French explorer Paul-Henri Nargeolet and OceanGate CEO Stockton Rush were on the sub and died in the disaster.

The debris field was found last Thursday by a deep-sea robot, also known as a remotely operated vehicle or ROV, from Pelagic Research Services, according to the company. On Wednesday, the company announced workers had completed "off-shore operations."

"They have been working around the clock now for ten days, through the physical and mental challenges of this operation, and are anxious to finish the mission and return to their loved ones," the company said in a statement on social media.

The company said it couldn't comment on the investigation looking into what caused the implosion that will involve Canada, France and the U.K.

"It's an opportunity to learn from the incident and then work with our international partners worldwide ... to prevent a similar occurrence," Neubauer told reporters Sunday.

The discovery of the debris followed a massive search effort for the sub. The Titan lost contact with a Canadian research vessel June 18 about an hour and 45 minutes into its dive to the wreckage of the famed ocean liner that sank on its maiden voyage in 1912.

Planes and vessels from several countries, including the U.S., focused on the search area approximately 900 nautical miles from Cape Cod, Massachusetts, for days before the debris field was located.

After the Coast Guard revealed the sub had imploded, a U.S. Navy official told CBS News the Navy detected "an acoustic anomaly consistent with an implosion" shortly after the sub lost contact with the surface. The information was relayed to the Coast Guard, which used it to narrow the search area, the official said.

Aliza Chasan contributed reporting.

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• Titanic
• Submersible