I could go on forever about this topic..I will post two to start
Kara Kopetsky
findkarakopesky.com
I believe that her boyfriend had something to do with it, There have been people witnessing him saying he killed her at parties etc. he wasn't liked by the family, and something is just off about his stories...I do not have hope that she is alive, which is very sad...
Lauren Spierer
Lauren's Wikipedia page
I feel like she died in a tragic accident and her friends and people she met know more than what they led onto know. I truly believe that her possible death was not purposeful, it's just sad that they won't come out with the truth.