I remember reading what I think are excerpts from this book, if not an article. If memory serves me correctly, the author did some very extensive detective work and, basically, found out that the so-called 'haunted boy' was nothing more than a rambunctious problem child. Considering the times in which he grew up, they probably didn't fully understand the extent of his issues, so they weren't equipt to handle him properly. The author even tracked down the actual guy 'The Exorcist' was based on, and, of course, he declined to make a comment of any kind.