If they had a case against him they would not have dismissed the charges. The charges were dismissed because there was insufficient evidence and they knew it. If they had gone to trial, and the case was then dismissed there, and that would have been the end of it. They were relying on the dirt on his boots matching dirt from the site HD's remains were found, but that turned out not to be the case. That, together with the window of opportunity being very small were the reasons they gave for dismissing the charges. If their case rested on a single piece of evidence then I would suggest that the case was not strong at all. And at this point I don't see what else they could possibly find. They dismissed the charges before going to trial to keep the possibility of refiling at a later date open, but realistically it is over.
Let me put it this way then, what case do YOU think they have? If you think there is a case, present an evidence chain that supports SA being the one responsible. I would be curious to see what your argument actually is. Over the years people have kept on asking why has he not been arrested yet, why is it taking so long, and that they think he is guilty, but they never say why they think that or why a conviction would be so certain if he was arrested. If everyone is so adamant that he is guilty, then surely they have a solid argument for why that is the case. What is the basis for their firmly held belief?
What would be the motive? I know that if there is compelling evidence for the crime then you don't need a motive, you only need to show what happened, but if there is little or no evidence then you most definitely do need a motive.
How would it have happened? Is there anything to support that it happened that way?
What was the window of opportunity? How was it determined? Could the accused have reasonably done it in that window?
Are there alternative explanations for what might have happened that could fit the known facts? Why are these alternative explanations not viable?
Those are the kinds of things that would be brought up in a trial, so you would need to have a good answer for them.
When SA was arrested, I did not understand why they did it since the facts, such as we knew publicly, in my opinion were insufficient to support an arrest let alone a conviction. My understanding was the current DA decided to re-examine the cold case, reinterviewed potential witnesses and on the basis of new evidence arrested SA. At the time we did not know what that evidence was. Speculation was that it was DNA since they apparently collected a DNA sample just prior to arresting him, although I did not see how a DNA specimen would have helped in this case since SA and HD lived together meaning cross contamination would be expected. Nor did I see what they could possibly have gotten now that they did not already have years ago. It would appear that this new evidence was actually the dirt on the boots. And when that turned out not to be the case after the FBI forensics looked at it the situation went back to insufficient evidence again.
