The Department of Corrections in Georgia said Wednesday that Troy Anthony Davis will be executed at 7 p.m. on September 21, 2011 for the 1989 murder of Savannah police officer Mark MacPhail. If the execution goes along as scheduled, advocates say it will be a devastating end to a troubled case.

There is no physical evidence that Davis shot the officer. The gun was never recovered, and  6 of the 9 eyewitnesses who testified against Davis have since recanted their stories.

Civil liberty groups including the NAACP, Amnesty International and the ACLU, along with individuals ranging from President Jimmy Carter to Archbishop Desmond Tutu, believe Davis should not be facing the death penalty because of all the discrepancies that have come to light in the case.

Even pro-death penalty advocates, such as former FBI director and federal judge William Sessions and former Georgia Republican Congressman Bob Barr have spoken out against executing Davis, citing "crucial unanswered questions" (Sessions) and a lack of the requisite fairness and accuracy required to apply the death penalty (Barr).

In June, human rights advocate and filmmaker Jen Marlowe wrote about Troy Davis for Colorlines.com with more details:

The "crucial, unanswered questions" include the fact that seven of the nine non-police witnesses later recanted or changed their testimonies, many stating that police coercion and intimidation led to their initial implication of Davis.

"After a couple of hours of the detectives yelling at me and threatening me, I finally broke down and told them what they wanted to hear," witness Darrell Collins wrote in an affidavit in 2002. Collins was 16 years old the night of the murder, and had been interrogated by the police for hours without his parents present. "They would tell me things that they said had happened and I would repeat whatever they said."

New witnesses have come forth identifying Coles himself as the shooter. "I saw Sylvester Coles–I know him by the name Red–shoot the police officer. I am positive it was Red who shot the police officer," Joseph Washington wrote in a 1996 affidavit.

Now that there is a final date for the execution, Davis’ last chance is with the Georgia Board of Pardons & Parole, which has the power to grant him clemency.

The odds, however, are not in his favor. There’s considerable evidence of a racial imbalance in who the government decides to kill. Marlowe wrote about the statistics earlier this year:

Davis’ case has become an emblem for much of what is problematic about a capital punishment system that is riddled with racism, economic disparity and error. Public capital defenders do not have the resources to properly investigate or litigate their overburdened case loads. Those with the means to hire decent legal representation are unlikely to end up on death row. Over 130 death row inmates have been exonerated since 1973, demonstrating just how many innocent people are convicted and sentenced to death.

According to a 2001 study from the University of North Carolina, a defendant whose victim was white was 3.5 times as likely to receive the death penalty in North Carolina than if the victim were non-white. A 2005 study in California found the defendant of a white victim three times as likely to be penalized by death. Growing realizations of these problems have led more and more states to question their death penalty policies. Earlier this year, Illinois became the 16th state to abolish capital punishment.