If it was Isaac, why were both parents lying about everything and being so inconsistent with their stories ?
At the very beginning I was very suspicious of Isaac. It seemed possible that he was the one that snatched little Deorr, and while pretending to go search for him, he could have stashed him somewhere instead?
People argued against that, saying he would not have had time to do so, and the dogs would have picked up the scent, if that was the case.
But the parent's behaviour was so problematic, I just kept coming back to them. They told false stories about store employees and diner employees, and the Beer distributor, playing with Deoor, ---employees who later denied those stories completely.
I don't see why that would happen, if it was Isaac who needed to hide his guilty actions. And wouldn't the parents have known it was Isaac, if it was as simple as that?
Also, why would the parents leave their busy toddler in the care of an elderly man, on oxygen, out in a remote park, alongside a rushing river? Who does that?