What chain of evidence is needed if the actual people involved say they saw something? Their testimony is not open to dispute, you either believe they saw it or you believe they are liars. How would that account be tampered with? Anyway, according to all involved, there is infrared and radar that corroborates the eyewitness accounts. Of course the Navy has that classified, but interestingly, there is no official denial to say otherwise. I think I will believe these people until the service shows me a real reason not to.