I had an epiphany moment watching the CBS special last night. I previously thought Patsy did it, but seeing the video of Burke refusing to say what was in the bowl (the pineapple) completely blew me away. He was so sheepish, absolute "deer in the headlights" when asked about it. He visibly reacted in an unequivocally guilty manner and his feet started bouncing almost off of the chair. That's the only time he exhibited those behaviors. He seemed sheepish, embarrassed, and caught. I have read every book, article, etc. and that was a cincher for me. I think as the special suggests, that it started over the pineapple. At some point during the night both children were up and around and about the house. Jon Benet took pieces of the pineapple that Burke was eating at the table, and ran down to the basement with Burke chasing her with the flashlight. He hit her with the near fatal blow, and poked at her back with the train track piece trying to revive her. She was still unconscious. From there, it's murky, but he eventually woke both Parents up, and the staging with the garrote and paintbrush ensued. The paintbrush was essential to also cover prior sexual abuse most likely by Burke that Patsy at least was aware of. Many, many times Parents will cover up sexual abuse amongst siblings, especially prominent families with an image to lose. Patsy knew a full check examination including vaginal, and questions to Jon Benet outside of her presence would be immenent at the Emergency Room, should she regain conciousness. As to who finished the poor victim off with the garrote, I'm on the fence. Let's face it, both Patsy and John were almost intelligent enough to pull off the perfect crime. The ransom note was a huge mistake and panic induced. They had to cover for Burke, they knew the head injury was severe enough to crumble their perfect house of cards. And they were angry at Burke, this is why the 911 call has John saying, "we aren't speaking to you." And also why they sent him away the next day, also to get him away from investigators. But, he was their only child left, and they did what they had to do to preserve their lifestyle by any means necessary.
From page 7/9, top partial paragraph of the JBR autopsy here: http://www.thesmokinggun.com/file/coroner-jonbenet-ramsey-autopsy?page=6
"...The proximal portion of the small intestine contains fragmented pieces of yellow to light green-tan apparent vegetable of fruit material which may represent fragments of pineapple. ..."
This material is not in the stomach and not in the duodenum, but in the proximal (first) part of the small intestine, and the extensive autopsy writing makes this clear. On the CBS show in one of the information boxes, it stated that food may be in the stomach about 5 hours. JBR had therefore ingested the pineapple at least 5 hours before death since the food had already moved along all the way to the small intestine. I think the theory that JBR grabbed pineapple from BR's bowl and then he hit her fails on this autopsy finding. JMO.