Medical professionals will formally analyse presumed human remains recovered from the wreckage of the Titan submersible.
The US Coast Guard (USCG) said it received debris and evidence from the sea floor at the site of the deep-sea vessel's fatal implosion, which killed five people.
British adventurer Hamish Harding and father and son Shahzada and Suleman Dawood were killed on board the vessel near the wreckage of the Titanic, alongside OceanGate Expeditions' chief executive, Stockton Rush, and French national Paul-Henri Nargeolet.
Large pieces of debris from Titan were transported to St John's harbour on Wednesday by the Horizon Arctic ship, where it was seen being unloaded by a crane.
Speaking after the evidence was recovered, the Marine Board of Investigation's chairman, Captain Jason Neubauer, said: "The evidence will provide investigators from several international jurisdictions with critical insights into the cause of this tragedy.
"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."
