Are the Russians behind the disappearance of American soldiers?

After uncovering the M88 HERCULES ARV (Armored-Recovery Vehicle) support vehicle sunk in the swamp, it was immediately assumed that 4 soldiers had drowned with it. It was even repeated by NATO chief Mark Rutte that the full crew of the vehicle had died, but it was not confirmed until then. Moreover, it was not even possible to scope Hercules, who is to be in the swamp at a depth of about 5 m.