If, as seems likely, the St. Louis County Grand Jury refuses to indict Ferguson cop Darren Wilson for slaying Michael Brown it won't be solely because of a weak, ineffectual, half-hearted, and highly selective presentation of evidence by the County prosecutor. It won't be because of massive counter pressure from Ferguson police and city officials, and police unions nationally to see that Wilson walks either. The biggest barrier to getting an indictment of Wilson and cops who kill unarmed suspects is the glaring racial and pro-police bias that deeply plagues the jury system and that includes grand jurors.

One study of grand jury actions against officers accused of deadly force found that indictments against them are almost non-existent. In Dallas, grand juries reviewed 81 shootings involving 175 officers from 2008 to 2012. Yet only one police officer was indicted. In Chicago only one police officer has been charged in an on-duty shooting since 2007. Grand jury indictments of police officers are so rare that when grand juries in North Carolina this year indicted two cops in two separate shootings of in each instance a black male, it made national news.

The typical grand jury consists of 16 to 23 jurors and those jurors are not screened for overt or hidden racial, gender, sexual preference or religious bias. This is far different from criminal court juries. Prospective jurors particularly in racially tinged capital cases are sharply challenged by both prosecutors and defense attorneys through oral examination, the use of lengthy questionnaires, and profiles, to root out hidden animus, especially racial animus. The scrutiny of jurors for bias is even more intense when the accused is a police officer and the victim is a young African-American male.

But even then, it's nearly impossible to ferret out hidden and overt racial bias. Two Penn State University studies on racial perceptions and stereotypes, one in 2003 and a follow-up study in 2008, found that many whites are likely to associate pictures of blacks with violent crimes, and in some cases where crimes were not committed by blacks they misidentified the perpetrator as an African-American. In a Gallup survey in June, 2014 that measured overall confidence in police, the police topped out among the three highest-rated institutions out of 17 tested in terms of public confidence, behind only the military and small business.

Despite overwhelming evidence that police do profile minorities, lie, cheat, and even commit crimes, jurors still are far more likely to believe the testimony of police and prosecution witnesses than witnesses, defendants, or even the victims, especially minority victims. The bias is further reinforced by pro forma instructions that grand jurors are given on how to judge the actions of a police officer who kills. They are told to always view the decision an officer makes to use deadly force through his or her eyes. The jurors in effect are challenged to put themselves in the officer's shoes when confronted with a supposed potentially life-threatening situation. Was the amount of force used reasonable and necessary to protect their life? Ray Hunt, president of the Houston Police Officers' Union, drove that point home. He noted that grand jurors empathize with police officers who face life-and-death situations, even if the suspect who is shot does not display a weapon. This is amply borne out in the not surprising fact that even though more than a quarter of the 121 civilians Houston Police Department officers shot in the past five years were unarmed, in the past decade no Houston police officer has been charged in any of the shootings.

It's an uphill battle to overcome both pro-police attitudes and negative racial stereotypes. Stanford University researchers recently found that even when many whites are presented with evidence that the criminal justice system is loaded with racial bias toward blacks they are more likely to support tough, draconian laws such as three strikes, tough sentencing and increased incarceration.

There are three blacks on the Ferguson grand jury that will decide the fate of Wilson. The presumption is often that having blacks on a grand jury will render them likely to be more willing to be more skeptical about the evidence, witness testimony and the officer's motives in using deadly force. That may or may not be the case. The evidence that these jurors receive from a prosecutor is no different than that given to the other jurors. If that evidence is selective, and heavily weighted toward the officer, than there's little likelihood that they will buck the prosecutor or other jurors and dispute the decision to exonerate an officer.

Wilson will likely skip away scot-free and if he does it won't be because of police clamor for him or a biased prosecutor. It will be because of the bias of the jurors that make up a deeply flawed grand jury system.

Earl Ofari Hutchinson is an author and political analyst. He is a weekly co-host of the Al Sharpton Show on American Urban Radio Network. He is the author of How Obama Governed: The Year of Crisis and Challenge. He is an associate editor of New America Media. He is host of the weekly Hutchinson Report Newsmaker Hour heard weekly on the nationally network broadcast Hutchinson Newsmaker Network.