The Ferguson prosecutor now admits that he presented a witness he knew was lying to the grand jury, but maintains the witness was not taken seriously. Of course, what he did was a breach of professional conduct and it could open the way for the appointment of a special prosecutor. "Under Missouri law (MO Rev Stat § 56.110) the presiding judge of the court with criminal jurisdiction — in this case Judge McShane — can appoint another prosecutor if the prosecuting attorney demonstrates a conflict of interest or bias. Courts have interpreted this provision broadly to include 'conflicts that reveal themselves through the prosecutor’s conduct in the case.'" See here.
It seems to me this rule is too narrow. District Attorneys have a daily working relationship with the police. Their failure to aggressively pursue cases against police almost automatically gives rise to the appearance of impropriety. Moreover, there is a conflict from the start. District Attorneys need to have a good working relationship with the police and prosecuting a member of a group that rallies around each other in times of crisis is almost certain to disrupt that relationship. The best response to this inherent conflict of interest is the appointment of an independent special prosecutor. Their is no good reason to wait until the prosecutor's conduct in the case reveals the obvious conflict of interest. Whether or not the conflict is "revealed" through the prosecutor's conduct, the conflict is there, and the rules should take the conflict into account.
Thanks to Tamara Piety for posting the above link on facebook.