Sorry, kinda new here. Just wanted to share my thoughts.
I strongly believe this was an inside job as well. I've been to girl scout camp before, I understand how those types of camps are set up. Whoever perpetrated these crimes had to have been familiar with how they were set up and how many campers were in each tent. That would have been difficult for an outsider to know. I also believe there was more than one person involved, one of those most likely being a female. It is incredibly difficult to subdue three girls at the same time without at least one trying to get away. Also believe the note threatening the campers the day before the camp opened was not a prank. The killers were trying to test out the waters, so to speak.
Here is a video that explains what I mean (this topic is further along in the video - the exact spot is in the video description):
https://youtu.be/JsulAguC6HI