The five-member Georgia State Board of Pardons and Paroles was to hold a last-ditch clemency hearing for Davis Monday.
Davis, 42, is set to die at 7 p.m. EDT Wednesday by lethal injection at Georgia Diagnostic and Classification Prison near Jackson.
He was convicted and sentenced to death in 1991 for the 1989 murder of Savannah police officer Mark Allen MacPhail, a 27-year-old father of two young children.
Multiple witnesses, including jailhouse informants, testified Davis committed the crime. But years later, several witnesses recanted or altered their original testimony. Some said one of the witnesses was, in fact, the killer.
Some jurors for Davis' trial now say they would have changed their decision.
"I would never have sentenced Mr. Davis to death and I no longer believe, beyond a reasonable doubt, that Mr. Davis was the shooter," juror Brenda Forrest told The Atlanta Journal-Constitution. "I feel, emphatically, that Mr. Davis cannot be executed under these circumstances."
But numerous state and federal courts upheld Davis' conviction and death sentence after reviewing the case. Repeated attempts to get a new trial failed.
Davis lawyers and supporters Monday are to speak to the parole board first, followed by prosecutors and then MacPhail's family members.
Under Georgia law, only this board has the authority to grant clemency, not the governor, as is the case in many states.
The board denied clemency to Davis three years ago, but has three new members.
If the board grants clemency, it will likely be to commute Davis' sentence to life in prison without the possibility of parole, Yale Law School Professor Stephen Bright, a death-penalty expert, told The Wall Street Journal.
King writes in her Saturday letter, USA Today reported, that her family is "well acquainted with the suffering and agony of losing a loved one to murder and the desire to see truth and justice prevail."
But "as we seek solace and justice, we must be careful not to perpetuate the chain of violence for the sake of expedience," King writes. "The law must seek justice knowing that the two are not always synonymous. In the case of Troy Davis, it falls to each of you to make it so."
By contrast, Mike Nichols, treasurer of the Savannah area Fraternal Order of Police lodge, told the Journal: "Every court said the same thing -- Troy Davis is not innocent. He was sentenced by a jury of his peers and that sentence needs to be carried out."
Wednesday marks the fourth date Georgia has set for Davis to be put to death by lethal injection. If it happens, Davis would be the 52nd man executed in the state since the U.S. Supreme Court reinstated capital punishment 35 years ago.