The commissioner of Tennessee's Department of Correction, Frank Strada, has resigned following a botched execution that left convicted murderer Christa Pike in critical condition, Governor Bill Lee announced Saturday, as the state halted further executions for the remainder of the year pending a review.

Pike had been scheduled to become the first woman executed by the state of Tennessee in more than 200 years. Media witnesses present at the execution, carried out at the Riverbend Maximum Security Institution in Nashville on Wednesday, said she remained alive for roughly an hour after being administered two rounds of the lethal drug pentobarbital, and could be heard snoring as they were ushered out of the viewing area. Witnesses said Pike told execution staff after the injection that her arm felt like it would "burst open." A court filing by her lawyers described pentobarbital as a caustic substance capable of burning skin, tissue and veins, and said Pike was taken to hospital afterward, where she remained unconscious and on a ventilator as medical staff worked to clear the drug from her system. The Death Penalty Information Center, which tracks US capital punishment data, said Pike is the first inmate known to have survived after being administered lethal doses of execution drugs.

Lee, who had previously denied Pike clemency, announced Strada's resignation and said further executions in Tennessee would be paused through the rest of the year pending a "comprehensive, third-party review." Lee thanked Strada for "his willingness to put the interests of Tennesseans first during this difficult moment." In his own statement, Strada maintained the department had acted properly: "I continue to believe the Department (of Correction) carried out its responsibilities in accordance with the established protocol."

A history of problem executions

Strada's departure has drawn additional scrutiny given his record overseeing executions prior to his Tennessee appointment. He previously oversaw what Fox News described as three "problem-plagued" executions while serving in a similar role in Arizona. Asked by reporters Thursday whether he bore responsibility for hiring and retaining Strada given that history, Lee did not directly address the question in his public remarks announcing the resignation.