There is too much doubt about the case to allow Troy Anthony Davis' execution be carried out Wednesday, his lawyers are telling the state Board of Pardons and Paroles.

Davis' legal team said it has "abundant evidence" that another man committed the murder for which Davis was convicted and sentenced to death. The lawyers say they also have obtained sworn statements from three jurors who sentenced Davis to death at his 1991 trial, but who now express doubt with their verdicts and are asking that Davis be spared the death penalty.

The plea for mercy is outlined in a 60-page clemency petition released by the parole board on Thursday. Davis sits on death row for the 1989 killing of off-duty Savannah Police Officer Mark Allen MacPhail. The courts have repeatedly upheld Davis' conviction and sentence and prosecutors say they are certain he is a cop killer who should be put to death.

Davis' clemency petition notes that seven of the prosecution's nine key witnesses have either recanted or backed off their testimony. Others have come forward giving sworn statements that Sylvester "Redd" Coles, who was at the scene with Davis and the first to implicate Davis in the killing, has told them that he was the actual trigger man, the petition said.

The board is scheduled to consider Davis' request for clemency during a hearing on Monday. The five-member board has the sole authority in Georgia to commute a death sentence to life in prison without parole on life with parole. The board has not said when it will issue its decision as to whether Davis should live or die.

It will be the second time the parole board has considered Davis' case; three years ago, the board denied clemency, but the board has three new members since then.

On Monday, in a closed-door session, the board will first hear from Davis' legal team and its witnesses, and will then hear from prosecutors and their witnesses.

"We are hopeful that Georgia will take this opportunity -- as many other states have done -- to show that the integrity of capital punishment is best preserved by reserving it for cases where no doubt exists as to the guilt of the accused," one of Davis' lawyers, Jason Ewart, said. "In light of the doubt cast on Troy Davis's guilt by all the new evidence and witness testimony in this case, the execution of Troy Davis will only weaken the perception of the legitimacy and fairness of our criminal justice system and capital punishment in particular."

Davis' innocence claims have spawned an outpouring of attention around the world. A march, led by Amnesty International and the NAACP, is planned today at 6 p.m., beginning at Woodruff Park and ending with a prayer vigil at Ebenezer Baptist Church. On Thursday, Davis' supporters gave the parole board 15 boxes of petitions with the names of 663,000 people opposing Wednesday's execution.

Brenda Forrest, a juror who sentenced Davis to death, said the new evidence would have had a great impact on her verdict, the petition said, citing her Sept. 12 sworn affidavit.

"I feel, emphatically, that Mr. Davis cannot be executed under these circumstances," Forrest said. "To execute Mr. Davis in light of this evidence and testimony would be an injustice to the victim's family [and] to the jury who sentenced Mr. Davis."

Another juror, Theodosia Johnston, said that after reviewing new information "I would have had doubt that Troy Davis was the person who shot Officer MacPhail," the petition said. "I do not want Troy Davis to be executed."

The petition also says there is new evidence and testimony that debunks the state's ballistics evidence and any suggestion that a pair of short pants found by police in a washing machine at the Davis home had blood on them. There are even more witnesses who now say that Coles told them he was the actual trigger man than there were when the parole board considered clemency the first time, the petition said.

"When all of the evidence -- both old and new -- is considered, the doubts in this case are so compelling that clemency is fully warranted," the petition said. "Indeed, short of those cases where DNA evidence conclusively proves the innocence of the defendant, if a commutation based on residual doubt is not appropriate here, it is difficult to imagine a death penalty case in which it would be appropriate."