We've seen all sorts of intruder theories, but none I've ever seen can explain 1. why a ransom note was left yet no one was kidnapped and 2. why the body was hidden in that tiny basement room. However, there is in fact a scenario that could account for these two things, though to my knowledge the only person who ever suggested it was someone on one of the anti-Ramsey forums arguing that this must have been what Patsy and John had in mind when they staged their kidnapping for the police. I'll get to that aspect in a moment, but for now, let's consider it purely as an intruder theory:
An intruder enters the house. Possibly a burglar. Possibly a pedophile. Possibly simply on a lark. Since there was no sign of forced entry, we can assume he has a key. He locates JonBenet, or simply encounters her, sexually assaults her, and kills her. Then he gets an idea. If he makes this look like a kidnapping, he could make some money out of it. He finds Patsy's notepad and writes a ransom note. Then he hides the body of his victim in the little windowless room, where no one is likely to look for it. He leaves the note where he assumes someone will find it the next morning. And then he is off. His plan is to call the Ramsey's home the following morning, as stated in the note, and instruct John as to where he should drop off the money.
This looks like a pretty good scenario, as it apparently accounts for some of the strangest aspects of the case: the fact that the note was written while the kidnapper was in the house, rather than beforehand; the fact that the victim was never actually taken from the home; the reason why the body was hidden.
But it also has some serious problems. First, it has many of the same problems as every other intruder theory: why no clear sign of the intruder; why is all the so-called intruder evidence inconclusive rather than the obvious evidence one would expect to see all over the place; why no footprints; why no fingerprints; why was nothing taken from the home; and if the intruder had a key, then what about the scene at the basement window, especially the suitcase propped against the wall, and also the packing peanuts from the window well, found on the floor beneath the window. Since there was no sign of forced entry at that window, or anywhere else, then how do we explain that suitcase and those packing peanuts?
There is also the question of why anyone would want to leave evidence that could be traced back to him, in the form of a hand written note? Or why that person would want to take so much time to write it, knowing someone might wake up and he could be discovered. If his plan is to collect a ransom, a note isn't necessary. He could simply have called the Ramseys first thing in the morning, with instructions on the ransom amount and where to deliver it.
The oddest part of this scenario concerns the "intruder's" plan as outlined in the note. For such a plan to work, this person would need to collect that money as soon as possible. Why give your victims time to think about what to do, time to have second thoughts and contact the authorities after all; time, also, for the body to decay and begin to smell -- sooner or later it is going to be discovered. Yet the kidnapper tells John to expect a call "tomorrow" rather than later that day. There's been some confusion over the meaning of that "tomorrow," but for the writer of the note there was no confusion at all. Clearly "tomorrow" meant tomorrow, i.e., between 8 and 10 AM the following day, i.e., the 27th, NOT the 26th, the day the note was found.
There is no way John could have collected the ransom prior to 8 AM on the 26th. Nor would there have been time for him to be "rested" as suggested in the note. The note writer clearly intended for the call to be expected the following morning. And if the "kidnapper" knows there is a body rotting away in the basement, waiting to be discovered, then why on Earth would he have wanted John to wait a full day before instructing him as to where to deliver the ransom? Under such circumstances, very clearly, the intruder would have called first thing on the morning of the 26th with his instructions, and would have wanted the money delivered as soon as possible.
So. Sorry if the heading of this post gave you Ramsey defenders out there any false hopes. My "new improved theory" is presented in the interests of completeness, to make sure I've left no stone unturned in the investigation of this case. As I see it, this is far more convincing than any other intruder theory I've ever encountered. But it too has some serious flaws. There is still no way to make sense of any intruder doing all that was done that night.
As far as something of this sort having been on the Ramseys' mind in staging their phoney "kidnapping," as was alleged by the author of the "new, improved" theory, this too won't hold water. If this was in fact what they had in mind when the police were called, then they did a good job of keeping it to themselves. To my knowledge, no such scenario was ever suggested by John, Patsy, or anyone else on their legal and investigative team. Certainly nothing of the sort was suggested by Lou Smit, who admitted he was unable to account for the intruder's motives in leaving a note yet not taking his victim. If this was what they were staging, surely they would have found a way to put that idea into the heads of the investigators. Since there is no sign they did any such thing, I see no reason to accept the author's original premise. It's an interesting theory. No more than that.