A former Adelaide mother facing the death penalty in the US over her stepdaughter’s death says the seven-year-old was prescribed pills by doctors that put her to sleep for 20 hours a day.

Prison guard and chaplain Lisa Marie Cunningham, 43, could become the first Australian woman on death row if she is found guilty of killing mentally ill Sanaa in February last year.

Speaking publicly for the first time, she claimed authorities were aware of Sanaa’s declining condition, acute schizophrenia, well before her death.

The Mannum-born mother of six claimed she and her husband — former Phoenix robbery squad detective Germayne Cunningham, 39 — are innocent of the first-degree murder alleged to have occurred in her adoptive Arizona hometown.

Cunningham said the family watched Sanaa changed from a “perfectly normal, vibrant six-year-old” to a dangerous, self-harmed child who attacked their pet dog.

“She’d forget how to do basic tasks like turn a doorknob or open a water bottle,” she told Matt Doran of the Seven Network’s Sunday Night from the maximum security Estrella Women’s Jail, where she remains in solitary confinement.

“For 10 months the state of Arizona was in our house watching her decline.

“They knew what was going on, ‘Call the doctors. Find treatment. Don’t give up’.”

Her lawyer, Eric Kessler, claimed the doctor who prescribed adult antipsychotic drug Risperdal never examined the child.

Cunningham said she had to bury her child because “nobody took it seriously”.

“We were jumping up and down, saying something’s wrong,” she said.

“I was irrational and I was hysterical with these people because they can’t give me a bottle of pills and take my six-year-old home so she sleeps for 20 hours a day.

“And then when she died of symptoms of Risperdal, we killed her. It makes no sense. Nobody was killed. Nobody was abused.”

A blood infection and pneumonia were blamed for Sanaa’s death.

Their children remain in state care.

Asked how “realistic” was the death penalty — which the Australian Government opposes — Mrs Cunningham replied: “You know, I think … I think it’s, I think it’s illogical, but do I think illogical things happen? Absolutely.”

Mr Kessler, who has tried 20 death penalty cases, told the program he had “never seen a worse travesty of justice”.

“Lisa is not a criminal,” he said. “She’s a loving mum. Australians should be horrified.”

The Cunninghams will remain in jail until their July 2020 trial.

THE VICTIM
Sanaa Cunningham was a very sick little girl. At the age of six she was diagnosed with acute schizophrenia. Lisa says she and Germayne watched a happy, healthy, normal little girl slowly slip away. They say Sanaa began injuring herself, scratching at her skin, gouging at her eyes. Even hearing voices urging her to kill.

Eric Kessler, Lisa’s lawyer, tells me Sanaa would defecate throughout the house and smear it. She would spin on her knees in circles, tearing the skin off her knees and legs. She once tried to harm the family dog.

Lisa and Germayne decided to pull the little girl out of her Phoenix school, to homeschool her. But Sanaa’s condition continues to deteriorate. Eventually they visit a psychologist who prescribes Sanaa a powerful, adult antipsychotic, called Risperdal – known to have side effects like pneumonia, and worse.

But as Sanaa’s health went from bad to worse, there were suspicions in the neighbourhood about whether Lisa and Germayne were really the loving parents they claimed to be.

THE CRIME
On Friday 10 February, 2017, Lisa Cunningham found Sanaa limp against her playpen inside her home in suburban Phoenix. She couldn’t open her eyes. She drooled. They called Sanaa’s doctor – the same doctor who had prescribed a powerful adult antipsychotic. Staff advised Sanaa’s parents to monitor her, and bring her in on Monday. The next day, Sanaa became catatonic. Her body was cold to the touch. Lisa Cunningham couldn’t get a reading from the thermometer, so she surrounded her stepdaughter with warm bottles of water.

Lisa rushed Sanaa to urgent care, about 1am, then to hospital. Hours later, around 5.30am on Sunday 12 February 12, she died.

At first, there was nothing suspicious. An autopsy found the little girl had dozens of scratches and injuries from her feet, to her head, but the Cunninghams said these were self-inflicted and a result of the schizophrenia. The coroner found the likely cause of death to be sepsis – a blood infection – and pneumonia (a side effect of Risperdal). But acting on a number of complaints, police would eventually take a closer look at what life was like inside the Cunningham family home. And they would ask three key questions: was Sanaa being neglected, was she receiving the best possible care, and did her parents act quickly enough when they realised she was gravely ill.

The prosecution facts, obtained by Sunday Night, allege that Sanaa effectively lived in a house of horrors for two years before she died. The details of that alleged abuse will be revealed on our program tonight, along with some startling allegations from neighbours. And as you’ll see, I ask Lisa some particularly uncomfortable questions. Was this little girl becoming too much of a financial and emotion burden? Is it possible Lisa and Germayne made the decision that it may just be easier to let her go?

THE EXECUTION
Arizona prosecutors have asked for the death penalty for both Lisa and Germayne Cunningham. It’s rare for them to push for capital punishment unless they think it’s a realistic chance of a conviction being achieved.

If Arizona gets its way, Lisa Cunningham would become the first Australian woman in US history to be put to death. I visited the desert outpost where the execution would be carried out, Florence State Prison, in a place colloquially known as ‘Death Town’. There have been 14 executions by lethal injection at Florence since 2010. One hundred and twenty-three inmates are right now eking out their final days on death row, awaiting their last meal. Only three of them are women.

Sunday Night was granted extremely rare access inside the prison, escorted through the gates to the compound known as Housing Unit 9, or the death chamber.

The last execution carried out in Arizona was four-years ago. To describe the process as botched would be a gross understatement. The prisoner – a murderer named Joseph Wood – took almost two hours to die. It should have taken 10 minutes. It should have been one injection – instead it was 15. People in the viewing gallery described hearing him gasping and snorting for air.

Maricopa County lawyer Bill Montgomery is unrepentant. When I ask him whether the death penalty system in his state is broken, he even floats a possible return to the firing squad.

THE VERDICT
There is not enough available public evidence to say for sure exactly how or why seven-year-old Sanaa Cunningham died. The prosecution is hinting at damning text messages between Lisa and Germayne. The defence dismisses these rumours, seriously questioning the validity of the messages and describing this as a monumentally flawed investigation, underpinned by a stunning police failure to properly tell the courts Sanaa’s time of death.

What is certain, is that someone failed Sanaa. In the inevitable blame game that is soon to be thrashed out in court, that sad fact must never be forgotten. There are so many unanswered questions. How, in 2018, does a child die from a preventable blood infection and pneumonia? Why was Sanaa prescribed a powerful adult antipsychotic in the first place, and was she properly evaluated? Lisa’s lawyers say the prescribing doctor didn’t evaluate her at all. If true, that doctor should not only be struck off the registry, but possibly charged himself.

Did the medical community do enough for a child with acute schizophrenia? Did Lisa and Germayne do enough? If Sanaa was as sick as is claimed, why wasn’t she relinquished to the care of an institution, to people properly trained to treat her? Why did authorities take so long to lay charges? Was this a case of preferential treatment for Germayne, a former Phoenix cop? Is this a case of police, prosecutors and child services trying to cover up their own failures? Supporters of the Cunninghams say the state’s murder theory is a house of cards that will rapidly collapse in court. Opponents insist Sanaa’s parents are exactly where they belong, and should pay the ultimate price.

“How realistic do you think the prospect of the death penalty is?” I ask Lisa.

“You know, I think... I think it’s, I think it’s illogical, but do I think illogical things happen? Absolutely.”