CBS Evening News with Norah O'Donnell, 06/23/23

The search for answers following the tragic outcome for the submersible that went missing in the atlantic. Officials say a catastrophic implosion destroyed the vessel and killed all five people on board. The Coast guard has reportedly declared the incident to be a Major marine casualty and will lead the investigation into the cause of the implosion. Security around Moscow is being tightened. The Russian media reports that riot police are protecting important facilities around that city. The news comes after the owner of the private Russian military contractor, the Wagner group, which is fighting on the side of Vladimir Putin, called on his soldiers to March for justice on the Russian capital.