Tennessee prison chief quits after failed execution of Christa Pike

The head of Tennessee's prison system is resigning after the failed execution of death row inmate Christa Pike, with Governor Bill Lee announcing on Saturday that Department of Correction Commissioner Frank Strada will step down this month.

The move comes as the state begins an independent review into why Pike's execution failed on Wednesday. Pike was later placed on a ventilator and remained unconscious in hospital, according to a court filing by her lawyers on Friday.

In a statement, Strada said stepping aside "is in the best interests" of the state while the review is carried out. The failure in Tennessee's execution chamber has led to demands for answers from both supporters and critics of the death penalty, and Lee has ordered an independent inquiry.

Pike's attorneys said hospital staff were trying to save her life and, as of late Thursday, were working to clear the two doses of pentobarbital used by the state to execute prisoners. Her lawyers said they believed problems with the IV lines caused the drug to flow into her body instead of her bloodstream. "Apparently at no point did any member of the execution team realise that the IV lines were not correctly placed or that the veins had blown and that the pentobarbital was, in whole or in part, entering Ms Pike's body," they wrote in the court filing.

Pike was 18 when she and her boyfriend tortured and killed a classmate, Colleen Slemmer, in what was described as a jealous rage. She later became one of the youngest women sent to death row. The failed execution has now triggered an independent review, led to Strada's resignation, and left Pike in hospital as questions continue over what went wrong.