Speaking to News.com.au, Dr Gail Van Norman explained: “It is a virtual medical certainty, that most, if not all, prisoners will experience excruciating suffering, including sensations of drowning and suffocation from [the lethal injection drug] pentobarbital.”

Expressing regret for the murder of Jennifer Long with his final words, Purkey said: “I deeply regret the pain and suffering I caused to Jennifer’s family. I am deeply sorry. I deeply regret the pain I caused to my daughter, who I love so very much.

“This sanitized murder really does not serve no purpose whatsoever.”

Shortly prior to Purkey’s execution, concerns had been raised that he was suffering from Alzheimer’s disease and so was unfit to be executed. According to AP News, the inmate saw Bill Clinton on TV the night before his execution and said he would vote for Clinton in the upcoming presidential election.

The convicted killer also requested pecan pie for his last meal, but asked to have it “later”, unaware that there wouldn’t be a “later”.