On Wednesday, Troy Davis, 42, is scheduled to die by lethal injection in a prison in Jackson, Georgia. It is his fourth execution date since 2007 in a case that has seen numerous legal twists and turns, with Davis's lawyers and thousands of supporters around the world protesting his innocence.
19 August 1989 – Mark MacPhail, a police officer in Savannah working at night as a private security guard, intervenes to help a homeless man who is being beaten by a man in a car park. MacPhail is shot twice and killed by the attacker of the homeless man.
23 August 1989 – Troy Davis is arrested and charged with the murder of MacPhail, based largely on the word of another man present at the shooting, Sylvester 'Redd' Coles.
August 1991 – Davis goes on trial. The jury is shown no physical evidence and the murder weapon is never found. But nine witnesses, including Coles, say they saw Davis shoot MacPhail. Davis pleads not guilty, saying he had seen Coles hit the homeless man, but had then left the scene before the shooting took place. The jury sides with the prosecution and Davis is found guilty.
30 August 1991 – Jury recommends death penalty, and Davis is put on death row.
September 2003 – The Atlanta Journal-Constitution newspaper begins to publish stories in which key witnesses at Davis's trial recant their testimony. In all, seven of the nine witnesses who said they saw Davis shoot MacPhail later changed their stories, several saying they had implicated Davis having been pressured by police. Other witnesses come forward to point the finger at Coles, saying that he had boasted that he was the real killer.
16 July 2007 – The Georgia Board of Pardons and Paroles grants 90-day stay of execution, just one day before Davis is scheduled to be executed.
23 September 2008 – At his second execution date, the Georgia supreme court and Board of Pardons and Parole both decline to get involved. The US supreme court in Washington steps in, delaying the execution pending its decision on whether or not to hear the case. Davis is spared just two hours before he is scheduled to die.
27 October 2008 – Davis's third execution date. The date is set after the US supreme court decides not to hear the case. Three days earlier, the Georgia court of appeals puts a hold on the execution to allow a new petition to be made.
7 September 2011 – After several more appeals fail, Georgia sets a fourth execution date for 21 September.
15 September – A petition with 663,000 signatures is delivered to the Georgia Board of Pardons and Paroles calling for clemency.
16 September – Jimmy Carter joins other public figures and celebrities in calling for a stay on the execution. "When there's doubtful evidence about whether someone's guilty, they certainly shouldn't be executed," he says.
17 September – Crowds march through the streets of Atlanta calling for a stay of execution.
19 September – The five-member Board of Pardons and Paroles hear pleas for clemency.
21 September – Davis is set to die on his fourth execution date.
21 September, 11.08pm ET: Troy Davis is executed four hours after the appointed time when the US supreme court refuses to grant a stay, dashing his hopes of a reprieve.