[bgill]

I lean toward the brother with Patsy covering up for him.

And John covering for them both. He disappeared for over an hour that morning during the time the "kidnapper" was supposed to call (Patsy didn't care the call never came), arranges for his pilot to get the plane ready and then finds JonBenet in the basement where his friend had previously checked and carries the body upstairs screwing up any evidence.

[CaptainK]

I agree.