Revenge for the high school downtrodden was an interesting premise but overall the book didn't fully work for me. I do give credit to the author for being willing to kill off a couple of the kidnapping victims rather than having them all miraculously survive. Especially since the heroine was close to one of those who didn't make it.
But I just didn't like the way too many coincideces/gaps combined. The teacher leaves behind the job listing so the victim's brother knows where she is heading next. Not a stack of potential jobs in multiple states, but conveniently narrowed down so he knows exactly where to find her? Meanwhile the brother is on the run from the FBI, who think he's the killer, but so far he's made like Dr. Richard Kimble in The Fugitive and evaded them.
How great a forger was the new student or how slack was the school administration? New guy waltzes in, he's got to have transcripts, test scores etc. in order to be admitted. Since he'd already graduated from high school, he either successfully created a fictitious history that fooled the administration or they were lax in checking his records. He didn't seem to have any trouble getting accepted.
Our killer teacher, despite just moving to the area, manages to find the perfect hideout to stash her victims that no one ever checks, despite the several massive manhunts for the missing students.
And, of course, the heroine has to go off by herself to the middle of nowhere without leaving anyone a clue where she is, but gets help from an unexpected source in order to survive.
Finally, the cyberstalker was a waste. He was more of a cyberwhiner and since it had been going on for a year before anything happened it was an obvious red herring. And why did it taker her so long to figure out the guy had to be a classmate?
Overall, good idea but not totally sold on the end result.