What about them leaving the door fully unlocked but Kate reporting the window was open, apparently broken into (or out of) by the would be 'they' who had taken her, yet the only DNA found on the window was kates. They also reported to the media before reporting to local police?
I personally believe Maddie was killed before that night they reported her missing which gave them time to get rid of the body and destroy evidence, think Gerry especially seems like he would be capable of abusing his kids, being blackmailed into faking the abduction or covering up her murder. Do not think the parents are innocent at all and I don't think she was murdered or abducted by strangers, only her family and their associates.