He works for Boeing, describes the part being from the stair assembly and coming off during flight. three days pass from the agents looking into the part and find it wasn't missing from the plane. it sounds like he told them were the piece goes. "describes certain technical information relating to the Boeing 727. I think they would all known if it was exterior the problem would never be solved as hundreds of them flew in that area. how it got there is unknown..this is in Boeings backyard..
Frankly, I think there's a better than not chance that the FBI F'd this up.
After all, how does the agent verify what was missing or not missing a year and a half after the flight? What documents did he review to determine what was replaced in Seattle after N467US arrived back on the 25th? They apparently completely missed the fact that the fiberglass panels went missing during the flight. What about some sort of metal clasps or something related to the panels, or stairs?
All I'm saying is that if the piece--whatever it is--came from inside the jet, it likely came from 305. In my mind the only alternatives are a hoax or someone stole a part from Boeing and dragged it into the woods for some reason and decided to leave it behind.
Unfortunately, the documents surrounding this metal piece are exceptionally thin on details per usual.