Tennessee officials failed to carry out the execution of Christa Pike on Wednesday evening, despite giving her two doses of the sedative pentobarbital, and she was taken to a hospital, her lawyers said. The Tennessee Department of Correction confirmed that Pike, 50, had survived the attempt. It said the protocol had followed every approved step and "does not allow for additional procedures beyond what was carried out this evening."

Pike, who would have been the first woman executed in Tennessee in at least 200 years, was due to die at the Riverbend Maximum Security Institution in Nashville. Seven journalists who witnessed the procedure said afterwards that she appeared to be alive and was audibly snoring. The curtain in the witness room was reportedly closed twice, and reporters were then escorted out. "It appears this did not go how this was supposed to go," said John North of the television station WBIR, who was among the witnesses. Her lawyers filed an emergency motion during the procedure, saying she had lost consciousness but still had a heartbeat. A federal judge noted that medical personnel had begun to give care. One of her attorneys told the BBC she was receiving "life-saving measures". Dr Joel Zivot, a medical expert retained by her defence team, said she probably never reached a sufficient blood level of the drug and that delays in resuscitation could cause brain injury. Her lawyers said the state had "once again failed to carry out a lawful execution" and argued that the case showed the risks of a protocol "veiled in secrecy".

The attempt came after a day of legal turmoil. A federal appeals court, the 6th Circuit, had halted the execution by a 2-1 vote about an hour before it was due, to examine whether Pike's allegations of childhood sexual abuse were fully considered at her 1996 sentencing. Tennessee's attorney general appealed immediately, accusing her lawyers of "abusive delay tactics". The US Supreme Court lifted the stay in an order signed by Justice Brett Kavanaugh. Justices Sonia Sotomayor, Elena Kagan and Ketanji Brown Jackson dissented, saying the ruling let the state execute Pike before challenges to her conviction could be properly considered. Governor Bill Lee had earlier declined clemency, and UN human rights experts had urged that the execution be halted.

Pike was 18 when she and her 17-year-old boyfriend, Tadaryl Shipp, killed 19-year-old Colleen Slemmer, a fellow student at a Job Corps training centre in Knoxville, in January 1995. Prosecutors said Pike feared Slemmer was trying to take Shipp from her. Slemmer was lured to a wooded area and attacked with a box cutter and a heavy object. A pentagram was carved into her chest, which fuelled fears of Satan worship during the era's "satanic panic". Shipp received life with the possibility of parole; Pike was the only one sentenced to death. She does not deny involvement and has been diagnosed with bipolar disorder and post-traumatic stress disorder. Her supporters point to her age, mental illness and severe sexual abuse from toddlerhood, which the state recently said it did not dispute.

Slemmer's mother, May Martinez, had said she had waited decades for the sentence to be carried out. "Not a day goes by, or a minute goes by that I do not think about Colleen," she told the Associated Press.

The case matters because executions of women are rare in the United States: 18 have taken place since 1976, about 1% of the total, according to the Death Penalty Information Center. Pike's condition was not known, and the outcome is likely to raise fresh questions about Tennessee's lethal injection procedures and what happens next.