I admit that I do not see an IDI as being probable, but to considering the 'possibility' of an intruder, once again, I'm trying to for a moment consider all sides of the equasion:
He had to, 'very well', know the R's house as well as the R's personally and professionally. (He had to know what made them 'tick'. He had to be able to predict correctly not only their day to day actions but also their emotions and how these emotions affected them in crisis. This would have only been sincerely evident when Beth died and maybe a little from PR's health problems.)
He thoroughly studied PR's handwriting in order to 'attempt to' duplicate it.
He had an awful grudge.
He either knew about JBR's prior sexual abuse or he was a part of it.
He knew that w/ a lot of help from him, the R's would, by their own nature, entangle themselves into this web and make themselves look even more guilty.
His grudge was so strong that he was willing to subject himself to the possibility of being caught by spending an enormous amount of time at the crime scene.
He was through enough to only leave one specimin of dna and 2 specimins of touch dna, and used everthing to complete the crime and all the evidence from within the home.
He has this horrific hatred for the R's, yet he has kept it a total secret from R's for 'x' amount of time prior to the crime and for over 10 years has kept totally silent after the crime.
(Could this new found touch DNA somehow 'draw him out' of hiding since he takes pleasure in the R's suffering and they have apparently been 'cleared'???)
He can carry a possibly 'still alive' child of 6 down a circular staircase in the middle of the night without difficulty or fear of awakening the occupants of the entire home or he boldly took her down the other staircase.
He knew where every item would be kept which he would need to successfully commit the crime as well as those needed for the staging would and he remembered to replace all items used but no longer needed in staging, exactly where they were previously kept.
He knew enough about JBR to be confident that he could find many of her favorite items to place with her to implicate her family. (Who could possibly be this close and not be in the group to have been tested for dna?)
He was able to enter and exit leaving no evidence of his entry or exit.
(I have a sinus headache from He!!... and am not communicating effectively at the moment... Would anyone else like to help me add to this list of "possible intruder facts which can be surmized" to justify rational for an 'possible' IDI's existance. If not, I need to take a break from thinking and from typing anything remotely coherent for a bit...I'll think more about this later, in the paraphrased words of S.O'Harah...) :bang: