Reply #23: As a devil's advocate...McGinniss has admitted that his "Jeff was

[ScreamingMeemie]

on drugs and that's why he did it" chapter was a theory. MacDonald actually had no drugs in his system at the time of the murders. MacDonald had approved McGinniss writing the book, no matter whether he ended up thinking him guilty or innocent.
Thanks so much for your comments. Your belief is exactly how I felt upon reading McGinniss' book, and then I watched the Unsolved Mysteries show, and found out that McGinniss actually recanted a lot of the book.