What witnesses say they saw during Christa Pike's botched execution

Christa Pike's attempted execution in Tennessee lasted for more than an hour, and witnesses say they could hear her every breath long after officials had administered a second lethal injection.

Pike, 50, was due to be executed at Riverbend Maximum Security Institution in Nashville on Wednesday (30 Sept), more than three decades after she was sentenced to death for the brutal 1995 murder of 19-year-old Colleen Slemmer.

A last-minute legal battle initially delayed the execution to provide judges with the time to ascertain whether Pike's allegations that she was sexually abused and raped as a child were considered when she was sentenced to death in 1996.

Pike, her then-boyfriend, Tadaryl Shipp, and the couple's close friend, Shadolla Peterson, were convicted over the killing of their classmate.

Pike, Shipp and Peterson all received very different sentences (WBIR/NBC)

The murder attracted widespread attention partly because a pentagram was carved into Slemmer's body, amid the wider 'satanic panic' surrounding alleged Satan worship in the US during the 1980s and 1990s.

Pike was sentenced to death in 1996, while Shipp, who was 17 at the time of the crime, received life in prison with the possibility of parole, and Peterson pleaded guilty to being an accessory after the fact, testifying against the couple and receiving just six years' probation.

After a period of deliberation following the halting of Pike's execution, the US Supreme Court ultimately allowed it to proceed, only for the process to go wrong in its final moments.

After the go-ahead yesterday, media witnesses were moved to a holding room with a clear view of the procedure.

Slemmer had been a student at the Job Corps, alongside Pike (First Coast News/ABC)

According to AP, officials then raised the curtains to the execution chamber at 7:27 pm, revealing Pike - who was 18 when she was sentenced for the murder of fellow Job Corps student Slemmer - strapped to a gurney.

The convicted killer was then allowed to make what were expected to be her final words, claiming she felt at peace with what was to come.

Pike said: "I’m going to leave this world the way I spent most of my life and that is in love."

However, instead of losing consciousness, witnesses heard that Pike remained awake during the procedure.

At one point, they say she even raised her head and questioned guards about a sensation in her arm, asking if it was supposed to feel that way.

The moment came as officials attempted to carry out the lethal injection using pentobarbital, with Pike's lawyers later saying in court filings that two doses of the drug had been administered.

Pike survived two rounds of lethal injection (Tennessee Department of Corrections)

By 8:26 pm, witnesses reported that the second dose had been given, but Pike still didn't die.

Even after the curtain was closed, attendees claimed they continued to hear Pike snoring from inside the chamber.

The microphone remained on until 8:53 pm, when it was cut off.

An announcement was then made telling media witnesses to leave the viewing area.

Pike's lawyers subsequently filed an emergency motion with the Tennessee Supreme Court, asking for the execution to be immediately halted.

They argued that Pike was experiencing 'unnecessary agony' and that continuing the process would violate her right to be executed without cruel and unusual punishment.

Pike was ultimately taken from the prison by ambulance, with her lawyers saying she was still alive, though her condition was not immediately disclosed.

Pike survived two rounds of lethal injection (BBC)

The Tennessee Department of Correction said officials had followed the state's established execution protocol.

The state has since halted its remaining scheduled executions for the rest of the year while a third-party review into what happened is carried out.

According to the Death Penalty Information Centre's executive director Robin M. Maher, several other inmates previously survived when execution teams were unable to access a vein, but no one had previously remained alive after receiving the drugs used in a lethal injection.

Maher described Pike's experience as 'singular and unparalleled'.

The state's execution protocol provides for a second set of syringes to be administered if an inmate has not died after the first set.

However, the protocol does not explain what should happen if someone remains alive after the second dose.