How many assistant district attorneys in the office that is investigating Scott Walker signed petitions to recall Scott Walker?

At least 19, according to Media Trackers. And 23 support staff.

Via Charlie Sykes, who says: "This would be the same Democrat Milwaukee County DA's office that has been conducting a nearly two year long 'secret' John Doe investigation of Republican Governor Scott Walker. The probe has been dogged by criticism of possible partisan bias, its selective prosecution, and frequent leaks."