The overarching arc of this season is the miniature killer. And I asked myself, last night, if Sara is the miniature killer.
Why? Well, let's see. Whoever mailed the package to Grissom knew that he was going to be gone and that he would be back. Nick commented that the timing device could have been set weeks in advance, so the killer knew to have it go off after Grissom got back, but just after.
But what got me started on this train of thought was the last scene where she's shaving Grissom. And that sent my mind connecting dots, though I can't say why.
Nick commented, in monster in the box, that it could have been someone with CSI knowlege. During Kepller's reign, he commented to Sidle (though he was making it about Grissom) that the killer had great attention to detail, which could have been foreshadowing.
And Sara was in foster care, though fostering a San Fancisco kid in Las Vegas might be a stretch, there are good reasons why it could happen.
I'm probably reading too much into this and it may just be that Sara is going to be a MacGuffin.