If John Ramsey killed his daughter, it seems unlikely he could have premeditated this act at any time prior to the night of Dec. 25th. If he had had time to plan, he would in all likelihood have written the note surreptitiously on a computer at his place of business and printed it there. The fact that the note is handwritten tells us he had no choice but to write it in his house, on the night of the murder.
The motive might well have been fear of exposure, resulting from some sort of incestuous relationship. At some time prior to midnight, after Patsy had fallen asleep, he may have lured her to an out of the way spot where they could be alone together. During that time, she might have had her pineapple snack. While they were alone together, she might have said something which led him to believe she intended to expose him. They were going to visit family the next day and JonBenet would then have had ample opportunity to tell other family members about some of the things she and her father had been doing. It is then that he might have decided he had “no choice” but to kill her. And conceived a plan for getting away with murder.
He could have initially struck her over the head to knock her out, making sure she would not suffer. Maybe he thought he’d killed her then. The simplest thing to do next would be just to get the body in the trunk of the car, drive to some secluded spot and dump it. He could then claim she’d been taken from the house by some pervert, molested and killed. But this would entail too many risks. Patsy might awaken to the sound of the car and the garage door opening. Neighbors might spot him driving away in the middle of the night.
After the note was discovered by Patsy, friends could be called in, to bear witness to the content of the note, that it was addressed to him, that the kidnappers wrote that they would be calling tomorrow, giving John plenty of time to do what he had to do. Those friends would then take Patsy and Burke to safety, while John was left to “raise the ransom and get it to the kidnappers.” What he really would be doing would be dumping the body and all the evidence, and destroying the ransom note, later claiming the kidnappers had insisted on getting it back. If his car had been spotted along the way, he could have claimed he'd been delivering the ransom, at the location designated by the kidnappers.
When the note was complete, John either traced or copied it from the computer screen, in order to disguise his handwriting. To be extra sure, he included a variety of odd details and tried very hard not to let his letters slant to the left, as they usually did. He only needed to fool Patsy and their friends. If his plan had worked, the authorities would never have gotten their hands on the note and would have had to rely only on what the friends could recall.
After writing the note, John could have returned to JonBenet’s body, only to discover that she was still breathing. To be sure she was dead, he might have strangled her. Then, thinking that possibly his prints might be recoverable from her throat (I don’t think they would be, but he might have thought so), he could have concocted the “garrotte” idea. If it looked as though she’d been strangled with this device, perhaps the investigators wouldn’t think to look for prints on her throat. As with the notepad and pen, he made sure to use nothing that would point to him when he fashioned the garrotte. Patsy’s things were handy and those are what he used.
His plan would have involved getting the body and all the evidence out of the house after Patsy and Burke had left with friends. In the meantime, it was necessary to hide the body in the house, along with everything else he would need in order to create the appropriate “crime scene” at the site where everything was eventually to be dumped. The little basement room was a logical choice. He would have placed the body on the floor, covering it carefully with the blankets so it could not be seen.
During this phase he might also have done some staging at the basement window we've heard so much about. It's possible he broke the window that night (though he would later claim to have broken it earlier, possibly after realizing the police were getting suspicious that the breakin was staged).
That morning, Patsy arose according to plan and found the note. John would have worked hard to convince her it was too dangerous to call the police. But a 911 call was placed anyhow. Possibly Patsy was a bit frightened by John, or too upset to think clearly. In any case, as we know, she made the call. There are reports that two calls were made, the first an abrupt hangup. Perhaps Patsy tried to call and John stopped her. Then, when he realized the police would be able to trace it, he let her make the second call.
The 911 call totally blew John’s plan and he may, that morning, have felt it was only a matter of time before the body was found hidden under blankets in that room, making it clear there was never any kidnapping and also that the body had been deliberately hidden, something no intruder would bother to do. Meanwhile, his friend Fleet White had already checked the basement room and, since the body was carefully concealed, noticed nothing amiss. Later that day, when officer Arndt suggested that John and his friends search the house, he jumped at the chance, went directly to the basement, opened the door, quickly removed the blankets, screamed and only then, as White noticed, turned on the lights. Later it was reported that John had said the body had been “right out in the open.”
After the body had been discovered, John realized it would look very bad for him if Patsy were to tell the police how he had fought so hard to convince her NOT to call them. He offered to talk to the police himself, since he would by then have worked out a story to tell, but refused to allow Patsy to be interrogated, claiming she was too upset. His actions at this point are, to me, especially revealing. If he and Patsy were in on this together, they would have been able to get their story straight and would have had no trouble “cooperating fully” with the police. If she had done this on her own, she would also have had a story prepared and would have WANTED to “cooperate fully” in order to dispel suspicion. As I see it, the only reason John wanted Patsy left alone is the fear she might talk about what transpired between them prior to the 911 call (and possibly one or two other things she might know that could be very damaging). It is this, in my opinion, that led to the long long delay before John and the lawyers finally consented to separate interviews.
I think it possible that Patsy may have sincerely believed, or wanted to believe, her daughter was killed by an intruder. After all, John had been "ruled out" as writer of the note. Also, since John had become her principal defender, she may have let herself be persuaded to go along with some “white lies” about what he might have said or done, since the truth might tend to make him look bad, even though he was in her eyes totally “innocent.”