Tennessee’s top prison official is stepping down in the aftermath of the failed execution of death row prisoner Christa Pike, the state’s governor Bill Lee announced Saturday.

Frank Strada, the department of correction commissioner, will leave his position later in October as the state launches an independent investigation into what went wrong during Wednesday’s botched execution of Pike, according to Lee.

Strada for his part said his resignation would allow that review to move forward in the best interests of Tennessee.

“Serving as commissioner of the Tennessee department of correction has been a great honor, and I continue to believe the department carried out its responsibilities in accordance with the established protocol,” Strada said in his resignation statement.

“Even so, stepping aside is in the best interest of Tennesseans as the independent review moves forward,” he said. “I believe this review is entirely appropriate and necessary, and I look forward to doing everything I can to help determine exactly what occurred.”

Strada handed in his resignation amid intensifying scrutiny of Tennessee’s closely guarded execution procedures after Pike was injected with lethal drugs on Wednesday but survived. She became the first death row prisoner in the US to undergo such an execution attempt and live.

Pike’s attorney Randy Spivey, who witnessed the procedure from inside the death chamber, described what happened as “cruel and torturous”. He said he personally counted seven needles inserted into Pike’s left arm, “one of which appeared to be bent when it was pulled from her”.

Attorneys have alleged that Pike’s failed lethal injection was the fifth “botched” execution carried out under Strada’s leadership in two states since 2022, as the Guardian reported on Saturday, hours before his resignation was announced.

Pike remained unconscious and on a ventilator at a hospital as of Friday, according to a court filing submitted by her attorneys. Her lawyers said hospital personnel were trying to save her life and, as of late Thursday, were working to clear the two doses of the execution drug from her system.

Wednesday’s extraordinary breakdown inside Tennessee’s execution chamber has triggered demands for an explanation from people on both sides of the death penalty debate. Besides ordering the independent review into case, Lee has paused the scheduling of executions in Tennessee.

Pike’s attorneys said they believe complications involving intravenous lines caused pentobarbital to enter her body rather than her bloodstream.

“Frank Strada’s resignation does not change the fact that Tennessee is shrouding its executions in secrecy,” Kit Thomas, a death row attorney in the federal public defender’s office in Nashville, said in a statement. “When Governor Lee hired Strada to fix execution problems in Tennessee his problematic history of executions in Arizona was well known. Strada then oversaw the implementation of a new protocol that ignored the recommendations of the independent investigation and weakened protections leading to a string of problems in Tennessee, including this week’s horrific botched execution attempt and another one in May. Until there is transparency and accountability, botched executions will keep happening.”

Pike, 50, was sentenced to death for the 1995 killing of teenage classmate Colleen Slemmer. Pike and her then boyfriend, Tadaryl Shipp, killed Slemmer at a job training camp in Knoxville.

A pentagram had been carved into Slemmer’s chest.

After the murder, Pike was diagnosed with bipolar and post-traumatic stress disorders, her attorneys said.

“It took me numerous years to even realize the gravity of what I’d done,” Pike had said in an earlier petition for clemency. “Even more to accept how many lives I affected. I took the life of someone’s child, sister, friend. It sickens me now to think I had the ability to commit such a crime.”

Had her execution that day succeeded, Pike on Wednesday would have been the first woman put to death in Tennessee in more than 200 years.

The Associated Press contributed reporting