The Coast Guard's Marine Board of Investigation heard from more than two dozen witnesses, including several former employees of OceanGate.

Karl Stanley, the owner of the Honduras-based deep-sea diving expedition company, testified on Tuesday during the U.S. Coast Guard hearing on the Titan implosion.

Friday marked the last day of testimony in the U.S. Coast Guard Marine Board of Investigation's two-week hearing into the June 2023 implosion of OceanGate's Titan sub.

Justin Jackson, a materials engineer with NASA, testified Thursday during the U.S. Coast Guard's hearing into the June 2023 implosion of the OceanGate submersible.

Don Kramer, the acting chief of the NTSB's materials laboratory, testified during the U.S. Coast Guard's hearing into the June 2023 implosion.

Don Kramer, the acting chief of the NTSB's materials laboratory, testified during the U.S. Coast Guard's hearing into the June 2023 implosion.

Guillermo Sohnlein testified at the U.S. Coast Guard's two-week hearing on the 2023 implosion that killed five.

Guillermo Sohnlein co-founded OceanGate with Stockton Rush, one of the five people killed when the company's Titan sub catastrophically imploded in June 2023.

A man who went on two OceanGate deep-sea dives to see the Titanic testified that he understood the risk and he could die if something went wrong.

Fred Hagen, who went on two OceanGate deep-sea dives, spoke at a U.S. Coast Guard hearing on Friday.

One witness described how Titan "malfunctioned" on a dive less than a week before its final journey.

A witness got emotional recounting the day of the doomed Titan submersible dive while testifying during the U.S. Coast Guard's hearing into the deadly implosion.

David Lochridge, the former director of marine operations for OceanGate, said he was known as a "troublemaker" in the company because he was so outspoken.

OceanGate's former operations director, David Lochridge, said he voiced safety concerns about the Titan submersible.

David Lochridge, former director of marine operations for OceanGate, testified he repeatedly voiced safety concerns about the Titan sub, saying he had "no confidence" in the way it was being built.

One of the last messages sent from the doomed Titan submersible during its June 2023 voyage to the Titanic wreckage was "all good here," the Coast Guard said.

"GMA" looks at a hearing that began Monday morning on the incident that left five people dead after their submersible imploded on a dive to the Titanic wreckage.

During its June 2023 voyage to the Titanic wreckage, one of the last messages sent from the doomed Titan submersible was "all good here," according to a U.S. Coast Guard.

One of the last messages sent from the doomed Titan submersible during its June 2023 voyage to the Titanic wreckage was "all good here," the Coast Guard said.

The family of one of the victims is suing the vessel’s parent company for $50 million over what happened on its voyage to the Titanic. ABC News’ Andrea Fujii reports.

The family of French explorer Paul-Henri Nargeolet, who had made dozens of dives to the Titanic site, filed a wrongful death lawsuit seeking more than $50 million in damages.

The estate of a Titanic researcher who was among the five people killed when the Titan submersible catastrophically imploded has filed a wrongful death lawsuit.

The investigation into the ill-fated Titan submersible's dive to the location of the Titanic will now take longer than expected, according to the U.S. Coast Guard.

Entrepreneur Larry Connor said this week that he and Triton Submarines CEO Patrick Lahey are planning their own deep-sea expedition in a submersible.

Less than a year after five people died aboard the OceanGate “Titan” submersible, Triton Submarines CEO Patrick Lahey and entrepreneur Larry Connor are planning their own deep sea expedition.

A former employee warned company executives about the inefficiency of their hull design and the company's testing methods.

The ABC series takes a closer look at the submersible that went on a quest to see the wreckage of the Titanic and ended in tragedy.

The Titanic has intrigued the public from the moment it tragically crashed into an iceberg in the Atlantic Ocean and sank on April 15, 1912.

OceanGate said it is suspending all exploration and commercial operations after five people were killed during its expedition to the Titanic wreckage last month.

OceanGate said it is suspending all exploration and commercial operations after five people were killed during its expedition to the Titanic wreckage.

Debris recovered from the submersible that catastrophically imploded while on a voyage to see the Titanic wreckage last week contained "presumed human remains," the U.S. Coast Guard said.

Debris from the submersible that catastrophically imploded while on a voyage to see the Titanic wreckage last week was brought ashore Wednesday morning.

Pieces of the Titan vessel were unloaded from the Canadian Coast Guard pier in St. John's, Newfoundland.

A visual timeline recounting the events that led up to the disappearance of the Titan submersible.

While the recovery operation and investigation remains ongoing, here's what we know about the situation and how it unfolded.

Investigators said they are speaking with more people connected to the deadly Titan submersible incident as more victims' families speak out about their grief.

The U.S. Coast Guard has formed a marine board of investigation, working alongside the FBI and international agencies to get answers after the submersible tragedy last week.

Karl Stanley, a submersible expert, says he warned of safety flaws when he took a trip on the Titan submersible in 2019.

The Canadian ship that launched the Titan submersible arrived in Newfoundland as international investigators search for answers.

Investigators search for clues in the deadly implosion of the Titan sub, including voice recorders abord the launch ship that could hold new answers.

The U.S. Coast Guard on Saturday is taking the lead on the investigation into the loss of the craft and the five people on board.

Liability waivers "are not automatically enforceable," one expert said of a potential case against the submersible company.

Authorities are looking into what may have caused the likely catastrophic implosion that led to the deaths of all five passengers on board OceanGate's Titan submersible.

The Navy used a Cold-War-era sonar system to detect and locate the sound's origin.

Titan victims' deaths ‘brought the world together,’ uncle says.

The company behind the missing Titanic tourist submersible exaggerated the details of the industry partnerships behind its titan submersible.

The Coast Guard policy is not to ask for a refund from private operators.

Guillermo Söhnlein says those that participated in their expeditions were treated as "key members of the crew."

Here's what we know about the crew of the OceanGate sub.

The Oscar-winning "Titanic" director and the ocean explorer who discovered the Titanic wreckage both share their thoughts on the tragic implosion of the tourist submersible.