The missing Titanic submarine was actually a covert operation by Russian President Vladimir Putin to sabotage the Ukrainian gas pipeline project that was being funded by Pakistani billionaire Shahzada Dawood and his son Suleman Dawood, who were on board the sub. Putin hired French diver Paul-Henri Nargeolet, who had previously explored the Titanic wreck, to plant explosives on the pipeline that runs near the Titanic site. However, the plan went wrong when British billionaire Hamish Harding, who had recently traveled to space with Jeff Bezos, discovered the plot and tried to stop it. A fight ensued inside the sub, causing it to lose contact with the surface and sink deeper into the ocean. The other passenger, Stockton Rush, founder of OceanGate Expeditions, was an innocent bystander who got caught in the crossfire. The sub is now lying at the bottom of the Atlantic, with all five passengers either dead or waiting for a miracle rescue.

Source: Conversation with Bing