There's a lot of relevant info in the thread called "Bones" that intertwines with the Bonfire subject. I'm only about half-way through that thread, as I keep going off to check links in there, and I'm only researching this in small chunks each day -- it's a very addictive case with so many things to think about and so few good answers that came up in the trial info presented in the series.
So far I think I've learned that there were three places with bones found: the quarry, the Janda's 'burn thing' (I've forgotten the word?) and the pit outside Avery's trailer...though there are also suggestions that some bones were scattered around the pit?
The temperature to get roughly that state of cremains would be around 1400 to 2000 celsius for about five+ hours?
There were allegedly about five tires in the burn pit bonfire (judging from the steel parts leftover) and this is theorized (thread on reddit with people who said they had qualifications in this aspect of anthropology and fires) to not be enough to get a high enough temperature for these results.
It was an open, outside fire, possibly adding to the difficulty of reaching those temperatures in a 'bonfire' which just has random junk and a few tires. As an aside, I remember seeing a TV documentary that discussed early human cremation of the dead and a wood-based cremation pyre has to be huge....this burn pit was supposed to be the size of a dining table (in area).
Then we have the difficulty of, if it does reach high enough temperatures, how do you get close enough for going into the fire and breaking up the bones? It would take time for that temperature to cool down, yet we supposedly have three known sites where the remains turned up.
Then we have the problem of knowing which is the actual burn site, and the extra query of whether there's an additional unknown site?
The bones, according to the forensic anthropologist who did study the remains after they'd been removed from the site, said that there was no odor (or residue) of rubber on the bones...an odor which I think most people would imagine would be insidiously permeating anything in the same fire? And the tires all seem to be agreed by all sources to have been present on the bonfire. Yet, according to the same expert's testimony, the bone fragments did seem entangled with the steel remnants of the tires, and actually needed physically 'prising' from the steel parts. But the expert couldn't say for sure if that was because both body and tires were burned together or whether they were mixed together post-cremation/bonfire.
The overarching problem that permeates all of these questions is the extremely wanting evidence-gathering process and the documentation of that (photographs of the burn pit prior to excavation seem to be non-existent, the bones weren't removed with the oversight of a forensic anthropologist, etc).
On the other side, we do have the difficulty of a third party accessing that property unseen to dump the remains. The coincidence that they'd have found this recently used burn pit, used on the say of Miss Halbach's disappearance, no less! This could be explained, though, if the person who did this (IF it wasn't SA) wasn't an unusual visitor to the scrapyard and they went there when he was out, maybe when Barb Janda and her son were out at work, Brendan at school, etc?
The problem I am having with all of this is that I am left with some important questions at the end of the series. Where was Teresa killed? How did it all play out? I think that when the police got Brendan's [false] confession of how it all went down that they assumed they'd got a rational narrative (or they created one out of the confession and the existing circumstantial evidence they'd collected). But without that confession, we don't have an explanation for how everything played out and where it all took place...without that, it's very hard to say for certain, with no doubts whatsoever, that it was definitely SA who was responsible and to just ignore the missing answers.
I would really like to see everything, on all the various topics, laid out similarly to how I've done in the first half of this post, but with links and quotes, and see what fits together and what does, like a jigsaw puzzle, because there has to be a coherent picture of what happened to Teresa, and so much of that is obscured right now.
