If the shoeprint was BR's it can't be proved to have been made that night. I am troubled by the shoeprint regardless of who left it. Here's why.
While I don't think JB was killed right there in the wineceller, she was obviously placed in there soon after her death or as she was close to death. Her livor mortis patterns indicate she was not moved, at least till livor became fixed, and by that time, rigor is setting in. So I assume the blanket was placed on the wineceller floor first, then JB placed on the blanket, and then it was wrapped around her torso. That was quite a bit of activity taking place in a small room to have a previous shoeprint survive.
I do know that many LE favor that type of shoe- haven't seen much about if the crime scene photo showing the print was taken before or after LE had been in that room.
If the print really is BR's - this was not a room the kids played in. While the home-made latch couldn't really have kept BR out because he could have simply climbed on a chair to reach it- there was not much in that dirty room of interest to kids. No good as a hiding place- the door can't be latched from the inside. So if it was BR's print, he was probably in there that night, though I suppose he could have been playing around in there that day- he had friends over. I have not seen anything from the Rs about whether BR could have been in the wineceller that day. This is surprising, because obviously they are aware the Hi-Tec shoe was being linked to BR despite their insistence that he did not own a pair, and despite BR's own comment to LE that he DID own a pair. His were sneakers. Not known if ALL Hi-Tec shoes have the same symbol on the sole.
If he was in there playing with friends, where are the other prints? If he was in there that night....well- then his presence at the crime scene kinda involves him in the crime, in some capacity at least.
Long ago I read that there was also a tiny bare footprint also found in that room. It is one of the ominous things you don't hear about when if true, you should be hearing a LOT about it. Was there a tiny bare print (assumed to be JB's) or not? Her body was found barefoot. NO mention in the coroner's report or notes whether any of the plentiful dirt, dust and mold from the wineceller floor was present on the soles of her feet. Scrapings from the soles of the bare feet OR shoes found on a corpse are simply a necessity when dealing with a murder victim. Was she standing in that room? If she was, she was obviously alive at that point. Was she and her brother(s) up to something in there? I find that hard to believe, but not impossible. Christmas night- a big day planned for tomorrow...parents up doing last-minute preparations for the trips.
We simply don't know enough about the prints in that room, and I find it suspicious that we don't. If the print is BR's and the bare print JB's- then he is part of the crime and THAT is why there has been nothing said about these prints. But that is not a theory I usually ascribe to. It does explain a lot though, especially why parents would cover up such a thing, including why a mother would write a note like that.