If true, this story would be lovely.  However, it's more likely it's a marketing gimmick.  Note the name of the island "Sveti Ivan".  That literally translates as Holy John ("the Baptist").

But who knows maybe Robert Langdon is alive and well and uncovering legitimate new reliquaries.  I could be wrong which, like I said, would be lovely.

problem why is its there when in reality its buried inside of a corner building that was buiilt by a mason for this one wrong dummy you found a rear end bone and it told you that it was that so there dream on