Charlie-Story wiht serial killer

[ciddie.livejournal.com]

I'm looking for a story I read a long time ago, unfortunately I can't find it. This is what I remember:
- the story is Charlie-centric
- there's a serial killer who murders members of some genius-group he wanted to join but was refused to (he's an FBI-Agent now and working with Don etc.)
- the finale is in the CalSci building, where the killer is chasing Charlie (who manages to nearly kill the killer himself with some self-built trap)
- the story is a little bit older, I think I read it at least two years ago (no guarantee), it was posted on fanfiction.net back then
Thank you!