Natalie is the killer and works at CSI as the janitor. During the episode you see her making the mini of Sara and we know how she got the car she sticks Sara under at the end (they were right about it). She got the car from a case Sara and Grissom worked on 6 weeks ago (we never see the case but we get flashbacks) and Natalie saw Grissom take a camera from Sara and stroke her arm as he does it. That's how she knows about their relationship. There is another case going on during the hunt for the mini killer but it's not as interesting as the mini killer one. I can't go though it all because of homework, but at one point Natalie brings the mini of Sara under the car in the desert and then it flashes to Natalie hiding behind a car in the CSI parking lot, and Sara coming out to put her stuff in the trunk of her car and going home. Natalie says "Sara?" and attacks Sara (they never say anything about Sara going to San Francisco). Then Grissom goes to his office and finds the mini and freaks, he calls Sara but she's gone. They catch Natalie but she won't tell Grissom where Sara is and Grissom panics. They show Sara at the end in the dessert under the car in the rain trying to pull her way out. Then it goes black and says "TO BE CONTINUED" (AHHHHHHHHH!!!!!!!!!!!)
Oh, and when everyone is looking at the mini trying to find Sara, Grissom says: "This girl holds me responsible for the death of Ernie Dell. I took away the only person she ever loved, now she's doing the same to me." (Greg, Nick, Warrick and Cath are all with him - also note the look Greg gives Nick, and Nick's reaction) .
I agree with what you said because I just can't wait until they show the season premiere. I am going to be tortured until they show it. I hope that they let Sara live. She is the best thing that has happened to Grissom.
She's also best thing that has happened to the show.
Grissom and Sara's relationship is too good for the show. It would be crazy to let so many devoted watchers down.
I say Sara will live.

As the CSI's continue their search for and discover the identity of the "Miniature Killer", Grissom and Sara's relationship gets exposed to the rest of the team as she goes missing during the investigation. The "Miniature Killer" is finally captured, but not before a member of CSI becomes the killer's final victim.