NPR reports that human remains have likely been recovered from the wreckage of the submersible that imploded during an underwater voyage to view the Titanic, the U.S. Coast Guard said Wednesday.

The news came hours after the announcement that debris from the Titan, collected from the seafloor more than 12,000 feet (3,658 meters) below the surface of the North Atlantic, had arrived in St. John’s, Newfoundland. Twisted chunks of the submersible were unloaded at a Canadian Coast Guard pier.

NPR notes that recovering and scrutinizing the wreckage is a key part of the investigation into why the Titan imploded last week, killing all five people on board. The multiday search and eventual recovery of debris from the 22-foot (6.7-meter) vessel captured the world’s attention.

“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,” Coast Guard Chief Capt. Jason Neubauer said in a statement released late Wednesday afternoon.

The “presumed human remains” will be brought to the United States, where medical professionals will conduct a formal analysis, Neubauer said. He added that the Coast Guard has convened an investigation of the implosion at the highest level. The Marine Board of Investigation will analyze and test evidence, including pieces of debris, at a port in the U.S. The board will share the evidence at a future public hearing whose date has not been determined, the Coast Guard said.

Neubauer said the evidence will provide “critical insights” into the cause of the implosion.

Debris from the Titan, which is believed to have imploded on June 18 as it made its descent, was located about 12,500 feet (3,810 meters) underwater and roughly 1,600 feet (488 meters) from the Titanic on the ocean floor. The Coast Guard is leading the investigation, in conjunction with several other government agencies in the U.S. and Canada.

The passengers on the ill-fated submersible were the head of OceanGate, which organized the dive, 61-year-old Stockton Rush; British explorer Hamish Harding, 58; Shahzada Dawood, 48, and his son, Suleman Dawood, 19; and French diver Paul-Henry Nargeolet, 77.

BBC video of the wreckage of Titan sub brought ashore:

Thanks to Alaric Bond for contributing to this post.