A "catastrophic implosion" - that's how the US Coast Guard is describing the conclusion to a multi-day race against time to find a submersible vessel that went missing near the wreck of the Titanic.
Below is everything we know about the disaster:
Who were the victims?
Hamish Harding, a UK billionaire; Shahzada Dawood, 48, and his son Suleman, 19; Paul-Henri Nargeolet a 77-year-old French explorer; and Stockton Rush, the founder and chief executive of the vessel's US-based operating company OceanGate.
What is OceanGate?
OceanGate launched in 2009.
The company gives people the chance to travel into the ocean on submersibles for closer looks at shipwrecks, including the Titanic.
Since its establishment, OceanGate has expanded from the US to conducting expeditions in the Pacific and the Gulf of Mexico, its website said.
"Become an underwater explorer," a company webpage providing information about the Titanic voyage stated.
What was the Titan?
The 'Titan' vessel was one of three of OceanGate's five-people submersibles.
In 2018, during a forum of submersible industry experts and a subsequent lawsuit by OceanGate's former head of marine operations, concerns about Titan's safety were raised, Reuters reported. The lawsuit was later settled that year.
According to media reports, a video game controller operated the vehicle. On the surface, OceanGate workers kept track of Titan's location and sent navigation instructions to the pilot via text message.
The implosion
It was too early to tell exactly when the Titan became doomed, the US Coast Guard has said.
OceanGate was the first to confirm the news on Friday morning (NZ time) all five people onboard had died.
That was followed by a detailed press conference, where the Coast Guard revealed debris belonging to the Titan on the seafloor had been found near the site of the Titanic wreck.
"The debris field here is consistent with a catastrophic implosion of the vehicle," said US Coast Guard Rear Admiral John Mauger.
"I can only imagine what this has been like for them and I hope that this discovery provides some solace during this difficult time."
