The debris and other material was collected on Oct. 4 and brought in for analysis.
“Who was the last person to murder two billionaires, at once, and have them pay for the privilege?” said fellow submersibles expert Karl Stanley.
“It seemed to almost be a nihilistic attitude toward life or death,” recalled Brian Weed, who participated in a test dive on the ill-fated Titan sub in 2021.
Five people died last month when a submersible imploded underwater during a trip to see the Titanic wreckage.
The announcement comes after the five-person submersible vanished during a dive to the Titanic on June 18. Authorities later said it imploded.
The submersible's thrusters malfunctioned on a dive filmed for a BBC documentary, leaving it circling at the bottom of the ocean.
"I’m so worried he kills himself and others in the quest to boost his ego," David Lochridge said of the company's CEO in the note.
The recovered debris and evidence from the submersible will be sent for further testing and analysis.
Photos show what appear to be several pieces of the submersible being lifted from the ship, including the nose cone with its distinctive circular window.
The agency has convened a Marine Board of Investigation, its highest-level probe.