When I was in college one of my history professors called in a
former police detective to speak to my historical research and writing
class. He told us how writing a historical paper -- be it for
publication or internal museum use -- is much like preparing a case
for prosecution. Criminal cases and research papers both have to be
unfailingly accurate and researched to the nth degree. Over the course
of the semester he read everyone's research work, and more often than
not took them apart like a defense attorney would. By the time he was
through with me, I hated his guts -- but I've never written a better
research paper.
        I know it's pretty unusual, but if you can find a retired
detective who is intersted in what you're doing, it will be woth your
while.