The US Coast Guard on Thursday said that the OceanGate Titan submersible suffered a ‘catastrophic implosion’ resulting in the deaths of the five members onboard. Rear Admiral John W. Mauger added that the search will be demobilized over the course of the next 24 hours.

Officials have not confirmed if they will be able to recover the bodies of those in the submersible. Tributes poured in for the five: British adventurer Hamish Harding, 58; Titanic explorer Paul Henri Nargeoloet, 77; Shahzada Dawood, 48, and his 19-year-old son Suleman; and OceanGate cofounder Stockton Rush.

Also read: How much did OceanGate Titan submersible hunt mission cost and will USA, Canada, France pay for it?

Several theories have come up as to why the submersible headed toward the Titanic wreckage site imploded. OceanGate is facing criticism for apparent faults in the structure of the submarine.

The Titan set off from its mothership – the Polar Prince – on Sunday. It was headed for the remains of the Titanic, which is approximately 3,800m below sea level. However, communications broke down within the next two hours.

Also read: Can Titan Five’s bodies be recovered from OceanGate submersible after it imploded?

As per several reports, there were no defects in the Titan’s design. It was to withstand a pressure of 5,500 lbs per square inch (Psi). The machine was lined by a five-inch-thick cylinder of carbon fiber.

However, experts are questioning the choice of carbon fiber over steel or titanium, of which vessels are usually made.

Reports also highlighted that OceanGate was alerted about certain safety concerns.

Also read | Did OceanGate Titan Submersible that imploded have a black box?

“Now is the time to properly address items that may pose a safety risk to personnel. Verbal communication of [these problems] has been dismissed on several occasions, so I feel now I must make this report so there is an official record in place,” OceanGate’s then director of marine operations David Lochridge wrote on 18 January 2018, according to a complaint filed by his lawyers.

His lawsuit was settled out of court. It claimed that he raised “critical safety concerns” about the vessel.

Also read | Terrifying AI video shows how OceanGate submersible might have imploded | Watch

“Issues of quality control with the new submersible were raised, as there were evident flaws throughout the build process,” the lawsuit alleged.

Filmmaker James Cameron quoted his sources in saying: “We got confirmation within an hour that there had been a loud bang at the same time that the sub comms were lost. A loud bang on the hydrophone. Loss of transponder. Loss of comms. I knew what happened. The sub imploded.”