I think the cops will know Misty is telling the truth, when she sits down with them, and implicates him and tells what happened that night. They know what happened, and know when Mistys story will be the truth, she just has to verify everything they already know, shes not there yet, that we know of. imo
I believe Misty would implicate Ron if she knew for certain he played a role in his daughter's disappearance. Misty said Ron never answered her question and explained why he didn't answer her phone calls before he suddenly showed up at the door. Was Ron lurking outside watching her freak out after she woke up and found the door open and HaLeigh gone? Possibly. The timing of his appearance is impeccable. If Ron was asked while under oath why he never answered Misty's calls, this case might be further ahead than it is today. Another good question to ask Ron on a LDT or under oath is: Do you want your daughter to come home? AFAIK, Ron had a key to the backdoor so he could have opened it and placed the brick there to make it appear like his daughter was abducted.