THE unprecedented botched execution of a woman in Tennessee has reignited the debate over execution methods in the United States – which varies from lethal injection to firing squads.

The condemned female murderer survived two lethal injections during a botched execution by the US state of Tennessee on Thursday.

Christa Pike, 50, was whisked from a prison execution chamber to a hospital Wednesday night, still alive despite two deadly doses of pentobarbital.

Methods used in the US

Methods vary by state. States carry out the vast majority of executions, while federal executions are rare.