The Harrowing (And Confusing) True Crime Story Behind Netflix’s ‘The Staircase’

The case is still highly contentious.

When Kathleen Peterson was found dead at the bottom of her staircase, the world found itself enthralled by her case. With her husband, Michael, at the centre of the investigation, dark family secrets and personal truths were revealed which threatened his innocence at every turn. Was he a loving husband grieving the loss of his wife, or was he potentially involved in her death? To this day, nobody knows for sure. 

Always eager to maintain its true crime presence, HBO has secured the rights to a series starring Colin Firth as Michael and Toni Colette as Kathleen. Below, the harrowing true crime story behind the now infamous case. The series is available to stream in Australia now, exclusively on BINGE

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What true crime case is The Staircase based on? 

The Staircase is based on the 2001 death of Kathleen Peterson, who allegedly fell to her death after tumbling down the staircase in her family home in North Carolina. Her husband, Michael Peterson, became the prime suspect in the case after foul play was suspected. 

On December 9th 2001, Michael phoned police to report that he had found Kathleen unconscious at the bottom of their stairs, having fallen down roughly 15-20 stairs. He claimed that she had mixed alcohol and Valium which likely lead to a loss of balance, causing the fatal fall. At the time of her death, Michael alleged that he had been sitting outside at the pool and had not heard her. 

According to the autopsy, Kathleen’s blood alcohol content was 0.07% which would have caused mild impairment of speech and vision. The coroner also found that she had sustained several injuries, the most concerning of which was seven lacerations to the top and back of her head, consistent with blows from a blunt object, with the medical examiner concluding that the incident was likely a homicidal assault. Experts estimated that Kathleen had died from blood loss around 90 minutes to two hours after sustaining the injuries. 

While many believed Kathleen and Michael to have a happy and loving marriage, the investigation uncovered a secret which threatened to undermine their family image. Michael was bisexual and was found to be having extramarital affairs, mostly with men. He claimed that Kathleen was aware of everything, but the prosecution believed that she had uncovered his secret life, confronted him and subsequently lost her life at his hand. This argument would form the crux of the prosecution’s case against Michael, while the defence argued that she had tripped walking up the staircase, fell backwards and hit her head on the door frame, causing the larger lacerations and extensive blood loss. 


At the time of her death, Kathleen and Michael had 5 children combined, though not all were biologically related to both. Caitlin Atwater was Kathleen’s biological daughter from her first marriage, while Clayton and Todd are both Michael’s biological sons from his first marriage. Michael also became the legal guardian of two girls, Margaret and Martha Ratliff after their biological parents passed away prior to him meeting Kathleen. Margaret and Martha’s parents were good friends with Michael and his first wife, which is why he was named as the girls’ legal guardian in the wake of their death. Disturbingly, their biological mother Elizabeth Ratliff was found dead at the bottom of a staircase, which became a key piece of evidence against Peterson during his trial. 

Kathleen’s only biological child, Caitlin was the only one who publicly condemned Michael and expressed that she felt he was likely guilty. After she called her siblings and explained her position, they stopped speaking. Both of Michael’s sons stood by their father, as did both of the Ratliff sisters. 


The ‘owl’ theory

During his trial, Michael’s defence team used what is now known as the ‘owl’ theory in an attempt to prove his innocence. The theory posited that Kathleen’s death was the result of a wild owl which had flown in through a window and attacked her, causing her to fall down the stairs. The defence team claimed that this theory was consistent with the lacerations on her scalp along with the injuries on her face and puncture wounds on her arms. 

Owls were known to live in the wooded areas surrounding the Peterson home and there are said to be examples of them attacking humans by dive-bombing the head. After re-examining the evidence, a microscopic feather and sliver of wood from a tree limb were found in a clump of hair in Kathleen’s hand that had been pulled out by the roots from her head, which was thought to have given the owl theory more credibility. 

Given the arguably bizarre nature of this entire theory, it garnered even more international notoriety for the case but was never actually presented in court. 


Where is Michael Peterson now? 

After one of the longest trials in North Californian history, Michael was convicted of murdering Kathleen in 2003 and sentenced to life in prison without parole. Peterson only served eight years, before being granted a new trial in 2011. Before it could commence, however, he submitted an Alford plea to the reduced charge of manslaughter. This plea signifies that the defendant does not admit to guilt but acknowledges that the state does has enough evidence to convict. In Peterson’s case, he did not want to go through the ordeal of a new trial as it ran the risk of another guilty verdict.

In 2017, Peterson was sentenced to time served and released after having spent 14 years in prison. He is said to currently reside in North Carolina in a one-level apartment. 

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