Numb3rs Fanfic Finders

I'm looking for a specific story but can't remember where I read it. 

The team was looking for a serial killer but didn't get anywhere, and Don asked Charlie to stop working on it. Charlie doesn't, however, and the suspect turns out to be Don.

Hoping for Help,
Evi

 This is a general request, but I haven't found anything like it in the tags. I'd like to read some stories where:

-Don is the main character
-Don uses his FBI-skills in an impressive way
-No math is used (or at least, not to solve the case)
-And the ending is (mostly) happy.

Preferably no episode tags. 

I'd like something in the vein of ALEO's stories (Pursuit, Caffeine, Vigilant Terrorist, Defense, Hunted), Reality of the Present., The Unquantifiable Variable, In a Mirror, Darkliy, or Time to Kill.

It doesn't matter if it's an official case or Don stumbles onto a crime in progress, but I'd like to be impressed by his skills - fighting, negotiating, leading, manipulating or otherwise. 

The fic can be canon or au, any POV, gen het or slash, any genre and as dark or light as it comes (provided that it ends reasonably happy), and, of course, the longer the better. 

Any help is appreciated!
Evi