If her body is out there, then its likely all three were involved because they need a vehicle to get it there.
I agree. I don't know how big this van der Sloot kid is but I'm guessing that he would have trouble disposing of a body all by his lonesome. They apparently did a pretty good job of it if she hasn't yet been found.
No matter which of their 'stories' we look at, VDS says the other two dropped him off at home, the two brothers say they dropped VDS and Natalee off by the hotel, it seems the brothers were the ones who had the vehicle that night.
So, I'm wondering why the police only impounded VDS car???
***BINGO*** That's exactly my theory. I think JVdS killed her, but the brothers helped him dispose of her body and think they'll be charged with her murder if they tell where she is.