Alright, so I haven't seen the film and it's been a while since it was released, but it's been bugging me for a long time. The entry on The Other Wiki says that the serial child killer killed his victims in pairs. Then why is the total number of children he killed an odd number (seven)?
From castleofspirits: "In all Parr took eight children, but only killed seven of them. He claimed that the woman in the black cloak appeared to him after he'd killed the seventh child and told him that he was finished and that he was to go into town the very next day and tell everyone what he had done. She said she would leave him alone if he did this. Parr released the last child, Kyle Brodie and cried doing so."
Ah, that clears up my confusion. Thank you.
How was the footage found in the forest that was meant to keep you from leaving?
The forest itself didn't keep people leaving—the main characters were very poorly equipped to go on any sort of hike, and as such didn't even need any supernatural influence to get themselves killed. Chances are that the supernatural influence liked to pick off small groups instead of large ones.
So somehow, the group that discovered the footage just wandered into a building, downstairs, then brought it back to civilization?
Presumably whatever force killed them is supposed to be sentient, and likely made the decision to let someone find the video and bring it back to the world at large. It apparently wants people to know what it's doing, given that it requires Parr to leave one of his victims alive and reveal what he did and why he did it before it leaves him alone.
Also, the backstory of the movie is that the footage was found underneath the foundation of a 100 year old house by a college archaeology group. Clearly, time and space in those woods is being messed with.
Although, note that the house could've just been 100 years old or close to that when the main characters went in, anyways.
Not just any house, but the basement of the Rustin Parr house. The footage was also described as having been in there for years if not decades. The Blair Witch is a LOT more powerful than a mere human sorcerer.
The forest doesn't trap everyone that enters. In many of the previous killing incidents there have been search parties looking for missing/murdered people who got home fine (with one notable exception being the Coffin Rock murders). Not to mention that the killings are spaced at least a few decades apart. The forest has its own rules on how it operates and obviously not by any human logic.
Or it operated on a kind of (crazy) human logic in the three film-makers' case, in that it targeted them because they were taking its spooky reputation so lightly.
For the fans that go with the idea that there's potentially nothing supernatural going on, there's a theory going on that they changed the flow of the river. How on earth would they be able to do that though? They'd need resources to be able to do that and also a window of time, which could potentially lead to a Plot Hole. And as far as I'm aware they had no time to do such a thing behind Heather's back, unless they just did it at night which also seems somewhat implausible to me, if you consider the difficulty of how hard it must be to accomplish such a thing while in the dark. And again, resources.
While the chances of that actually being the case are very slim, it's worth noting that if Heather is making a documentary, she needs to get permission well in advance to make the film to avoid a lawsuit - and she's clearly done her research on locations etc. So she had to have gone to Burkitsville before and asked around, so the locals would have heard about a documentary. So that does give them a window of a few weeks to prepare something. But yeah, no time to do so physically behind Heather's back.
As a note to the above: apparently they not only diverted a river—with no signs of construction, digging, filling, any disturbance to the nearby plants or animals—but also fooled the compass with powerful natural magnets? I'm sorry, but at that point, "a witch did it" is more plausible than whatever was supposed to be happening there.
The orginal ending WAS going to be that the locals did all of it to prank them.
