>I have to wonder - - once you figure out that the panties
>belonged to JonBenét, why does it need to be discussed like
>this? I don't see this leading to the capture of the killer.

It is not intended to lead to the capture of the killer.
It is intended to wear down the witness, to remove some line of defense, to amplify some existing media speculation into something even more damaging, etc.

It can have alot of reasons, but not one of them is ever going to be "the capture of the killer". That is not the purpose of the proceedings.