Georgia halted the planned Monday execution of the only woman on death row in the state due to problems with the drugs to be used in the lethal injection, officials said.
Kelly Renee Gissendaner, 46, condemned for the murder of her husband in 1997, would have been the first woman executed by the state in 70 years.
"Within the hours leading up to the scheduled execution, the Execution Team performed the necessary checks. At that time, the drugs appeared cloudy," Georgia Department of Corrections spokeswoman Gwendolyn Hogan said in a statement.
"The Department of Corrections immediately consulted with a pharmacist, and in an abundance of caution, Inmate Gissendaner's execution has been postponed," Hogan said.
It was not immediately clear to when the execution would be rescheduled.
Prosecutors said Gissendaner plotted with her boyfriend, Gregory Owen, to kill her husband, Douglas Gissendaner, who was stabbed to death in a desolate area in suburban Atlanta after being abducted from his home.
Owen confessed to carrying out the February 7, 1997, murder and implicated Kelly Gissendaner. He is serving a life sentence.
Gissendaner's execution by injection was reset for Monday night at a prison in Jackson, Georgia, after a winter storm prompted state officials to postpone it last week.
The Georgia Supreme Court on Monday afternoon turned down Gissendaner's request for a stay of execution.
Gissendaner's attorneys had also asked the State Board of Pardons and Paroles to reconsider its decision last week to deny her request to commute the sentence from death to life without parole. The board denied that request on Monday.
Her lawyers made an 11th-hour argument to the US Supreme Court after an appeals court rejected her attorneys' request for a delay, saying that Georgia's lethal injection process is not transparent enough to be challenged in court.
In a Supreme Court filing, they argued that the court also should note that she did not kill her husband herself and had reformed herself.
In their clemency petition to the parole board, Gissendaner's lawyers said the death row inmate has "accepted responsibility" for her actions and has "shown a commitment to seeking redemption through spiritual growth and serving others."
The state last executed a woman on March 5, 1945. Lena Baker died in the electric chair but was granted a pardon in 2005 after officials said she should have been given clemency for killing her abusive employer in self-defense.
