The very thing that has frustrated the Cooper investigation for 50+ years also attracts people to this mystery.. That is, we have very few 100% facts, try listing them. This case is the ultimate bayesian example. We take a few facts, some conflicting and lots of inferential info and try to reconstruct the crime, it is a fascinating intellectual challenge where we as individuals utilize our own unique experiences, history, education, logic and reason.
The Cooper case is the ultimate intellectual puzzle challenge.. a test of our own minds..
The problem is there may not be a 100% provable conclusion.. without forensics.. so, we do the best we can with what we have and that includes consistently re-examining the evidence and exploring new theories that fit within the information we have.
It is like having a 10,000 piece picture puzzle with 300 confirmed pieces and only 1,000 more pieces that may or may not even belong to that puzzle.. We try to put enough pieces together to establish the full picture... lots of pieces fit that may not even belong..