The dayslong search for Titan has come to a devastating end as officials turn their focus to what caused the "catastrophic implosion" believed to have killed the five people onboard.

The U.S. Coast Guard said on Thursday that debris discovered in the search for the sub was consistent with a catastrophic explosion. The debris was found off the bow of the sunken Titanic, officials said.

A U.S. Navy analysis of acoustic data had “detected an anomaly consistent with an implosion or explosion” near the Titan around the time it lost communications, a senior Navy official said. The sound was not definitive, but it was immediately shared with commanders, who decided to keep searching, the official said.