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The main support ship of the Titan submersible has returned to a Canadian harbour following the deep-sea vessel’s fatal implosion.
Flags on board the Polar Prince were at half-mast as it arrived at the port in St John’s in Newfoundland on Saturday morning after four passengers and the pilot of Titan were killed in the incident.
The support ship is set to be the subject of a safety investigation from the Transportation Safety Board (TSB) of Canada.
Canadian Coast Guard (CCG) boats had already started to return to St John’s harbour on Friday as the recovery operation began to wind down.
British adventurer Hamish Harding and father and son Shahzada and Suleman Dawood were killed on board the Titan submersible, alongside the chief executive of the company responsible for the vessel, Stockton Rush, and French national Paul-Henri Nargeolet.
In a statement issued before ships began to return to the port, the CCG said the search and rescue operation had concluded.
The CCG confirmed one its vessels would remain on the scene and would “provide assistance and support to the recovery and salvage operations as requested by Maritime Rescue Coordination Centre Boston.”
The TSB said a team of investigators had been deployed to St John’s to “gather information, conduct interviews and assess the occurrence”.
In its own statement, the safety body said the investigation would be carried out “in accordance with the Canadian Transportation Accident Investigation and Safety Board Act and international agreements”.
The TSB will not determine civil or criminal liability and conducts investigations for “the advancement of transportation safety”.
The investigation comes after the BBC reported that emails from Mr Rush showed he had dismissed safety concerns over the Titan submersible.
In the exchanges with deep-sea exploration specialist Rob McCallum, OceanGate’s chief executive said he was “tired of industry players who try to use a safety argument to stop innovation”.
The Titan submersible lost contact with the tour operator an hour and 45 minutes into the two-hour descent to the wreckage, with the vessel reported missing eight hours after communication was lost.
In the days that followed the report that Titan had gone missing, the US Coast Guard said the vessel had a depleting oxygen supply that was expected to run out on Thursday.
A report from The Wall Street Journal said the US navy had detected a sound in the search area for the submersible on Sunday that was consistent with an implosion.
The Associated Press, citing a senior military official, reported that the navy passed on the information to the Coast Guard, which continued its search because the data was not considered by the navy to be definitive.