Originally posted by: WesyeedI'd say testimony from different eyewitnesses of the event is substantial enough evidence to permit further investigation. 
Further investigation is always welcome. However, other than hearsay we have no other leads. Nobody has a recording of it, it seems. Remember, many "eyewitnesses" claim to have seen the Anchorhead scenes in the film as well... which wasn't possible, since it never even had finished sound.
--SKot