This explanation was just about the call Beth received from the chaperone when they discovered her missing.
The big "I KNEW she was kidnapped" was only a mother's intuition, because Natalee was never late for anything? I bet Natalee never got into a car alone with three strange men before, either. Don't get me wrong, my heart breaks for Beth, but I was hoping they had evidence in a phone call that was enough to get the state troopers and FBI right on the case, and not just "I KNOW my daughter MUST have been kidnapped!"
It really sounds like there were 2 phone calls. One to Beth's cell phone and another one somewhere else (home phone?). Remember when Greta was interviewing Beth tonight and she asked her if she had talked to Natalee during the time she was in Aruba? Beth said something to the effect of if she HAD called she would have known there was something wrong.