When LE went into the lower campground, no one was seen entering or exiting.
(Snipped by me)
About this specific point, hasn't it been said that the POIs and little DeOrr were the ONLY people camping at the lower campground? In that case, all LE would likely have is their word on whether someone entered or exited the campground before searchers or LE arrived. No external witnesses that we've been made aware of.