US murderer Christa Pike unconscious and on ventilator after failed execution, lawyer says

Pike's lawyers filed an emergency motion on Friday to preserve "any and all evidence" related to her botched execution.

Hospital staff are working to save her life and clear the drug used, pentobarbital, from her system, the filing states.

During the execution attempt, prison officials tried to start intravenous (IV) lines by using at least seven needles on Pike, according to her lawyers.

At one point, Pike herself offered guidance of where they could try.

"One needle was bent in a 90-degree angle when it was removed," the filing states.

While receiving the two doses, "she could be heard crying, whimpering, and breathing loudly throughout the procedure", her lawyers said.

Tennessee Governor Bill Lee ordered an independent review into Pike's botched execution and he halted all executions in the state for the year.

The state's department of correction has defended the method it used, saying "the protocol does not allow for additional procedures beyond what was carried out".

Authorities are yet to say whether they will try again to execute Pike. They have not not offered any explanations about what went wrong.