I'm not surprised that there's nothing to be found at the crash site. Generally, unless in an inaccessible place, recovery vehicle wise, such as a mountain or in deep water, they tend to pick up the pieces hand haul them away.
You should try the Naval Safety Center in Norfolk.
http://www.safetycenter.navy.mil/
Go to the bottom and click to contact the PAO. He/She should be able to tell you what to do to submit an official request for the report.
Rich