Mystery of the Ostara yacht - S1.E4

In 1920, in the Black Sea, near the Danube Delta, a yacht full of gold belonging to a very influential and wealthy Russian noble family ran aground. The victims were fleeing the Bolsheviks. Even the number of victims is not clear. There are said to have been 13 dead, but other sources speak of 11 or 12 people shot. Two of the victims were discovered 2 months later on an island 2 kilometres away. The treasure on the boat - kilos of gold, cash and jewellery - was never found. Was it group suicide, was it murder? Where is the treasure? Who are the perpetrators?