I think it's fair to say the evidence is strong when the victim's body is found on the accused's farm, when the victim's car is found in the accused mother's driveway, when the victim is burned in an incinerator belonging to the accused, according to major newspapers, when the accused has no reason to own a livestock incinerator, when credible witnesses identify physical features which lead police to trace the accused. Honestly, I can't imagine what you'd consider strong evidence if not this.
Snowballing, as you put it, is what I alternatively described asmistake piling up upon mistake upon mistake. ONe mistake leads to others. Clearly, a wrongful conviction has to star somewhere. The point is it ends up being lots of people making lots of mistakes that checks and balances should prevent, but don't because they usually aren't used when they should be.
Here is the Innocence Project on causes of wrongful prosecutions. Which causes do you believe apply to the Millard case?
http://www.newenglandinnocence.org/knowledge-center/causes/
So I could theoretically break into your garage or shed, steal some of your tools, use them to murder someone, then burn that body in your BBQ, and leave their remains on your property, and move their vehicle to your Mom's house, all while wearing a wig that emulates your haircut, (or if you have a tattoo, I might ink that on my arm), and according to your scenario above, this would be strong enough evidence for everyone to conclude that you are the guilty party. And any initial evidence will back that up, if this were the case, so it would be possible for LE's initial assessment, that you are guilty, to lead them to seek out evidence which agrees with their view.
If that mistake was not caught, if no other suspect looked good, then it snowballs into something further. Next, everyone in the media would rip apart everything in your life, looking for anything that might even hint at anything unusual. One of your grade school bullies can come forward and claim you were a glue eater and your mother wore army boots. Someone who knew someone who was missing can see an opportunity to maybe find the missing person by jumping into the spotlight and claiming you were the last person to see them alive. And then once that happens, now LE are rethinking your close family member's recent suicide and suddenly finding it suspicious. Snowballing; that's how it can happen.
Again, I am not asserting that this what happened in this case, I still maintain that I do not know enough to cast my judgement yet. I am arguing that this is, I think, one of the reasons why some people still have doubts and not everyone considers the evidence so far to be as strong as some others seem to feel it is. Beside, we don't even know what the actual evidence is, we only know what the media has told us, and again, and are not always right, and they specialize in snowballing.
This is all my opinion only.