A crime investigator asks these questions.
1. Was there a motive?
2. Was there an opportunity?
3. Is there evidence?
4. If the answers are “yes,” and I delve into this, will anyone publish it? (This was pre-Internet.)
5. If the answer is “probably not,” why should I risk getting assassinated? (See Belzer & Wayne, Hit List)
6. If I live to tell about it, can I afford a lawyer to defend me in a libel lawsuit?
After the suspect is dead and gone, a university historian asks these questions.
1. Is this a conspiracy theory?
2. What happens to the careers of university historians who publish conspiracy theories?
This leaves independent authors and odd-ball book publishers.