The downer with civil charges is that if Birk were forced to pay restitution, I believe (not certain) that he could escape through bankruptcy. The SPD (read TAXPAYER) would wind up covering the cost. I would assume that the SPD had some sort of insurance for something like this (like a malpractice type coverage) but I honestly don't know. Personally, I'd rather see Birk do some time. If it were someone in my family, I couldn't see closure without a sentence.
Of course the other possibility is that with the DOJ being in town, they could file under a civil rights charge. I'm not huge on federalism though, so I'm on the fence about the feds coming in to do the job that the King County prosecutor won't.