As a preface (and caveat) to my post, I haven't followed this case until very recently and I certainly do not have an in-depth knowledge of it. However, I think that the three who were convicted for it are likely innocent. At least of this crime. It's my impression that this case is an example of how "messy" crimes can be: They sometimes happen to and around bad people, undesirable people, mentally ill people, misfits, ill-equipped LE, crooked LE, coincidences, and all manner of other aspects of life.
Usually, I am on the side of believing that those who have been convicted are guilty, but reading through this case, I'm really surprised at how many people are so adamant at the guilt of these three, although as far as I know, there is really no evidence to tie them to it.
That being said, I do have a theory, which does, indeed, involve at least three men (hence, the three knots) two of whom are actually connected to the crime scene. I have no doubt that the M3 could have been involved in the occult (vs. merely exhibiting the "trappings" of such, which is often the case) but I don't know of any occult references at the scene. (Perhaps I am wrong on this, please let me know if I've missed that.) There is a case to be made, however, which weaves together crime scene evidence, statements made by the friend of the boys, timelines, and other known factors, combined with what we know about real life, which would explain the crime well, and includes a convincing motive. I'm not sure I want to go into it all here for various reasons, not least of which is that it's likely been debated much here in earlier threads, but I do think the M3 were sort of a red herring in this crime. I seriously wish that those responsible would be held accountable.