Christa Pike remained alive after Tennessee tried to put her to death by lethal injection, making her the only inmate to have survived after the drugs were administered.

What happened to Pike on Wednesday is “singular and unparalleled,” said Robin M. Maher, executive director of the Death Penalty Information Center.

The failed execution also came after an eight-hour delay while the U.S. Supreme Court considered whether to postpone her execution.

Pike, 50, was still in the hospital Thursday afternoon in critical condition, and her lawyers said they did not know her long-term chance for recovery.

Here's what to know about Pike's execution:

Pike's execution was supposed to start at 10 a.m., but a federal appeals court stopped it about an hour before. The state appealed to the U.S. Supreme Court, and it took eight hours for the conservative majority to overrule the lower court and let the lethal injection with the barbiturate pentobarbital to proceed.

About 90 minutes later, prison officials raised the curtain to the execution chamber, where media witnesses saw Pike strapped to a gurney with an IV in her arm. She said she was leaving the world with love.

“I’m ready to be free,” she said. This is a happy day.”

She sang a song with her spiritual adviser, looked around and after several minutes said her arm was hurting or burning and asked if it was supposed to feel that way.

The curtain to the witnesses was closed then opened again around the time a second dose of pentobarbital would be administered. Pike appeared to lose consciousness, but she continued breathing and at times made snoring-like noises for the next hour.

Prison officials closed the curtain for good about 40 minutes after they first opened it. Pike's attorney demanded a telephone to ask a court to stop the execution.

It's unknown what was happening to Pike from the time the curtain closed for good at 8:06 p.m. until her attorney was told an ambulance was coming and witnesses were told to leave around 8:50 p.m.

“We at this point do not know the ramifications of the chemical torture that she has endured," Pike's attorney Randy Spivey said.

Prison officials have not said when their attempt to kill Pike turned into life-saving efforts. They have only released a statement saying their lethal injection protocols were followed.

Within hours, Tennessee Gov. Bill Lee canceled the state's last execution of 2026, scheduled for Dec. 3, and ordered a comprehensive third-party investigation into what went wrong with Pike.

“It needs to be done thoroughly and however long that takes, whatever process is required to make sure we get to the very end of it and all the questions are answered,” Lee said.

It's not the first time Lee has ordered an investigation into capital punishment in Tennessee. Four years ago, an independent review found the state didn't follow its own execution rules and failed to properly test lethal injection drugs. That probe came after an April 2022 execution was stopped because of mishandling of drugs.

In May, Tennessee stopped the execution of Tony Carruthers after medical workers who got an IV into his right arm couldn't get a secondary IV line after trying his other arm, his left hand and his left foot, then failing to establish a central line. The governor ordered officials to wait at least a year before trying to execute Carruthers again.

Pike's lawyers called for the governor to now spare her life.

“Christa has endured punishment greater than any other person in the history of the American death penalty. The governor must commute Christa's sentence now,” Spivey said.

Pike’s legal team told the courts and Tennessee prison officials that she had medical conditions that would make death by lethal injection agonizing.

They said Pike suffered from a condition with elevated platelets known as thrombocytosis. They argued the condition could cause issues with blood clotting at injection sites or bleeding that could affect her lungs.

Medical workers also had trouble drawing blood from her, and setting an IV line is a harder process, her lawyers said. Spivey said he counted at least seven spots where needles were put into her left arm Wednesday and that at least one needle bent on an unsuccessful attempt.

Pike’s biggest fear from being executed wasn’t “a fear of dying. It was a fear of a prolonged, painful, traumatic death. And that’s what happened minus the death,” said Stephen Ferrell, an attorney for Pike.

Pike didn't deny she killed 19-year-old Colleen Slemmer in 1995. The two were classmates at Knoxville Job Corps.

Prosecutors said Pike feared Slemmer was a romantic rival and lured her to a secluded area where she and her boyfriend slashed Slemmer with a box cutter and beat her with a large chunk of asphalt. The case got widespread attention because of the brutality of the killing, the ages of the people involved and because a satanic symbol was carved into the victim’s body.

Pike said she was sexually abused starting from when she was a toddler and that she was raped at ages 11 and 17. Her lawyers said her death sentence was unfair because she was 18 at the time of the crime and the jury wasn't told about the abuse and how that might have affected her behavior.

Slemmer's mother witnessed the execution attempt and said her daughter didn't get justice.

“I watched the whole thing. She was awake. She was laughing. She was moving her head, moving her feet. She was trying to sit up. Didn’t work the first time they gave her a shot. It didn’t work the second time so she’s in the hospital and alive," May Martinez said by telephone.

Tadaryl Shipp, Pike’s boyfriend, has admitted that he was the one who carved a pentagram, a star-shaped symbol associated with Satanism, into her body. He was 17 at the time of the killing and was sentenced to life with the possibility of parole because of his age.

___ Kim Chandler in Nashville and Russ Bynum in Savannah, Georgia, contributed to this report.