My gut says he didn't do it. Too much was on the line for him and there was a lot of funny business going on that wasn't reported by the police.
I don't really get the "too much on the line" argument. I get that he was in line for a large amount of money, but anyone who commits a crime like this has "too much on the line" specifically the prospect of life in prison or even death in some cases, yet it happens fairly regularly. Negative consequences often don't carry that much weight with people with poor impulse control.
Also, I'd say the flip side of this is that Avery may have felt somewhat bullet-proof with his case against the county. Maybe he felt that he could coerce, or even force Halbach into things and the county would be scared to come after him lest it look like a witch-hunt. But then it got out of hand and he killed her.
If you think Avery is innocent; what are your thoughts on the evidence; the car and body mostly? Was the car planted there, or did someone else on the Avery compound kill her and hide the car? And was the body burned behind Avery's trailer, or moved there? Was it just dumb luck Avery had a bonfire that night?
The impluse control may be a huge factor. That is one aspect that I'll never personally be able to wrap my head around, but do agree that it happens far too often. SA may have shown signs of poor impulse control in the past as well. Maybe he did just snap in the heat of the moment. But to be fair, I think that can also be said for other potential suspects that the police failed to follow through with.
So the evidence itself does not make any sense. Crime scenes are either the garage or SA's bedroom according to the State's case. I'm almost 100% positive it happened somewhere else. By who or when.... no idea.
The blood smear in the back of the RAV 4 indicated that Teresa was bleeding from the head and transported in the vehicle. This alone doesn't support the killing in the garage or bedroom and then moved to the burn pit initially. The burn pit was right off of Avery's garage and house IIRC.
As far as the two locations in which bones were found, I can't see a reason why SA would kill her on his property. Drive her out to the gravel pit. Try to burn the body there, just to bring pieces back to his own property. If SA killed her, he would have tried to burn her in his own pit first and move the remains off site. But that goes back to my last part. Why use a car to move a dead body 20 feet?
Back to the RAV 4, someone noted that the tires had dried sand between the wheel tread. I'm personally curious to see if there are forensics that can confirm the RAV 4 was actually being driven within the gravel pit area.