IF there was a genuine accident (ie DeOrr fell in the water or fire or fell or got hit by a vehicle) you would think they'd have called for an ambulance immediately. I'd like to know what time Jessica's multiple calls to Trina were, how many there were, how long was it before 911 were called, were 911 called more than once? Why did Vernal need to go hauling down the road for a better signal knowing that Jessica's phone was working fine in getting through to her mom. Why did he really leave? How long was he gone?
I think that if DeOrr was at the campsite, and really did disappear after lunch but before the 911 calls, the only person who could have removed his body in the timeframe is Vernal. He is the only one that we know left the campsite in a vehicle. Jessica said they searched the vehicles straight away, but what if Vernal was the one who searched the vehicle he'd hidden DeOrr's body in saying "he's not in here" before driving off in it? From what we know I don't think any of the others could have hidden a body within walking distance of camp without it being discovered by now.
And then there's the theory that DeOrr was never there at all. In which case they're all lying. Why? Why would Isaac lie about that? Is he so loyal to grandpa he'll go along with whatever - "just say you were fishing when he vanished, act vague, but tell them you saw him playing happily earlier". No obvious sign of DeOrr at the campsite or indeed in Leadore. And I get why Grandpa might cover for Jess, but why Isaac?
Or, maybe little Deorr really did just wander off and one of these days someone will find him curled up WAY beyond the search zone, complete with toy cars and wellies. Time will tell hopefully, sooner rather than later would be nice though!
Bit ramble-y, bedtime!!