but, in III, Connie was utterly devoted to Michael. Why would she play those games? It sounded to me like she really believed Fredo drowned. And how deep could that lake be? Maybe, like Dexter, the currents in the water take corpses awwwwayyyy.
I think Connie was just telling Michael what he needed to hear
because of that devotion. She knew full well what happened. She just didn't want Michael to worry himself into another diabetic stroke.
And for the record,
Lake Tahoe is one of the deepest lakes in the entire country, and the tenth deepest
in the world, measuring over 1600 feet in some spots. It's also said that the pressure in that deep a body of water often prevents corpses from creating the natural gases necessary for a corpse to float.