Can someone please explain why...? spoilers obv

I was wondering this as well and actually hit up this film's forum to ask the same question. It felt as if a continuation of that scene had been cut for whatever reason.

I was also curious as to why the captive woman in the "dungeon" had a gag over her mouth even though she obviously had enough range of motion with the chains on her wrists to reach up and pull the damned thing down. Who the hell wouldn't pull a gag away if they had the opportunity to do so? More of an observation concerning a clear lapse in logic than a question, though...

The missing girl was a red herring. She was not the same girl that was approached by the dad with the tire iron. We were meant to believe that the family had the girl, but she drowned. Probably swept away in a flood.

I thought perhaps the dad dumped the body in the river so there would be a body that went missing but was found. If all those people were never found that is more suspicious.