Gary's execution was scheduled once before, in 2009.
Records from past executions show the lethal drug generally starts flowing within a couple of minutes of the warden exiting.
Carlton Gary was convicted in 1986 on three counts each of malice murder, rape and burglary for the 1977 deaths of 89-year-old Florence Scheible, 69-year-old Martha Thurmond and 74-year-old Kathleen Woodruff.
In the late 1970s, a serial killer stalked Columbus, Ga., raping and murdering elderly women. On Wednesday, the state of Georgia gave their answer and by Friday morning of this week, Carton Gary will be dead by lethal injection.
Police later linked the 67-year-old to four other murders but, while evidence and a confession fingered him as the killer, lawyers insisted he could have been cleared by testing that was not available at the time.
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Gary was accused of attacking nine elderly women from September 1977 to April 1978, seven of whom died.
Absent some action by the federal courts on his last-minute appeals, he is to die by lethal injection at the state Diagnostic and Classification Prison in Jackson.
The victims were all older white women who lived alone and were sexually assaulted and choked - usually with stockings, prosecutors said during his trial.
The parole board met Wednesday to receive information for or against clemency and announced its members have been reviewing the parole case file on Gary for the past several weeks. Gary was only charged in three, but prosecutors believe he also carried out the other attacks.
"Carlton Gary is scheduled to be executed this Thursday by Georgia, despite the fact that physical and scientific evidence developed long after his trial proves that he is likely innocent of the crimes for which he was sentenced to death, including DNA evidence that the only eyewitness identifying Gary at trial was mistaken in her identification", wrote Gary's attorney Jack Martin in a statement released to the press.
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One of the reasons behind throwing out Gary's appeal, as the Georgia Supreme Court explained, was that his lawyers did not submit the additional application for a discretionary appeal to the Court and instead re-submitted an "original motion".
The state has argued in court filings that the evidence Gary's lawyers present as new has already been considered by the courts and that his convictions and sentence have repeatedly been upheld by state and federal courts over the past three decades.
Meanwhile Eggers was put to death at 7:30pm on Thursday, after dropping his appeal in 2016.
After more than 10 attempts to place a needle, the execution was called off. That evidence would have raised reasonable doubt in the minds of the jurors who convicted him, they contend.
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