Chilling true story of 'The Staircase Killer' revealed as tragedy is turned into HBO series starring Colin Firth

Fans of true crime will undoubtedly be familiar with the story of Micheal Peterson, aka "The Staircase Killer".

Back in 2001, he was accused of killing his second wife, Kathleen, after she was found dead at the bottom of a staircase in their family home. The resulting trial, which is infamous for its twists and turns, was the subject of Netflix's 2004 documentary, Death on the Staircase.

Now, Michael Peterson's life and crimes are to return to our screens again. Colin Firth will be starring in the HBO Max limited series, The Staircase, and the eight-episode series will be based on the original docuseries about Kathleen's death – as well as a number of books and reports about Peterson's case.

Ahead of the new series, we take a look back at the true story of the "Staircase Killer".

Michael Peterson was accused of killing his second wife, Kathleen (Credit: Netflix)

Who is Michael Peterson?

Peterson is an American author behind several memoirs about his experience in the Vietnam War. He once controversially claimed that he had won two Purple Heart medals. One for being shot, and the other for being hit by shrapnel from a land mine.

However, he later admitted that the first wound was from a car crash that happened after the war. And there is no actual evidence that he ever received another medal.

Before Peterson met Kathleen in 1986, he lived in Germany with his first wife, Patricia Peterson, who was an elementary school teacher at an American military base. According to People, they had two sons, Clayton and Todd.

During this time, Peterson and Patricia befriended Elizabeth Ratliff. She was a local mother to two girls, and her husband was killed on a military mission. The Peterson's connection with Ratliff will later become important to the story...

is the staircase killer based on a true story? The Staircase Killer was turned into a Netflix series in 2004 (Credit: Netflix)

What is the story being The Staircase Killer?

On December 9th, 2001, Peterson's second wife, Kathleen, was found dead at the bottom of the stairs in the North Carolina home they shared.

"My wife had an accident," Peterson frantically told emergency services on a 911 call. "She's still breathing. She fell down the stairs."

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He claimed that Kathleen had slipped and fallen to her death after drinking wine and taking Valium earlier in the evening. However, the crime scene looked suspicious due to the amount of blood on the stairs, and the fact that she had died from blood loss. In law enforcement's opinion, the blows were consistent with the use of a blunt object.

Per the medial autopsy, Kathleen had sustained a slew of severe injuries, including a fracture to the thyroid neck cartilage and multiple lacerations to the top and the back of her head.

As a result, the case zeroed in on Peterson — who incidentally was the only person at home at the time of her death.

"This was not an accident," said Durham County D.A. Jim Hardin. "There is no question."

Peterson claimed that Kathleen had slipped and fallen to her death after drinking wine and taking Valium (Credit: Netflix)

What was the evidence against Michael Peterson?

After probing into Peterson's life, the police quickly started to form a compelling case against the now-77-year-old.

They discovered that he was bisexual and had had relations with men outside of his marriage. While Peterson alleged that his second wife accepted these relationships, prosecutors during the trial said that she had only found out recently, and had confronted him on the night of her death. This, they said, was enough motive to charge Peterson.

Kathleen's $1.5 million life insurance policy was also seen as a factor.

In a more damning turn, however, they uncovered that a close family friend, Elizabeth Ratliff — whose daughters were later raised by the Petersons — had been found dead at the bottom of a staircase. This was 15 years before Kathleen was discovered in the same manner.

When Ratfliff's sister, Margaret Blair, heard of Kathleen's death, she phoned the detective working on the case. "I said, 'Are you aware that the same thing happened to Margaret and Martha’s mother and Michael Peterson was the last one to be with her?" she told NBC.

Ultimately, when Ratliff's body was exhumed by the prosecution, a new autopsy determined that her death was also a homicide. Peterson was never charged with her death.

the staircase killer Police discovered that Peterson had been having affairs (Credit: Netflix)

Who was Duane Deaver?

One of the testimonies that led to Peterson being found guilty was from Duane Deaver. He worked for the State Bureau of Investigation, and examined the blood found at the scene of Kathleen's death. Deaver determined that she had been beaten to death.

There were major flaws in his evidence, however. It came to a head when Deaver was fired from the Bureau in 2010 for falsely reporting blood evidence in other trials.

So, while Peterson was convicted in 2003 of beating his wife to death, and sentenced to life in prison, he was released eight years later when a judge ruled that Deaver had given misleading and false testimony about the bloodstain evidence.

the staircase killer Peterson was released after serving eight years in jail (Credit: Netflix)

What happened with the owl?

In one of the most bizarre twists, the murder was actually pegged on an owl.

The Peterson's neighbour, lawyer T. Lawrence Pollard, looked at the investigation in 2009, and went through the crime scene evidence. He discovered that Kathleen had been holding clumps of her own hair in her hands. Within the strands were tiny feathers and wood splinters and cedar needles.

Pollard knew that barred owls, which are native to the area, had attacked some joggers around the time of the murder. So, his theory was as follows: Kathleen was attacked by the owl outside, and got it entangled in her hair. After she was attacked, she rushed inside, and tripped in a panic, hitting her head.

The evidence was quite compelling. Per The Mirror, Dr Patrick T. Redig, from the University of Minnesota's veterinary department said that it was "entirely within the behavioural repertoire of large owls".

And Mary Jude Darrow, Peterson's second defence attorney, thought it was a viable theory based on Kathleen's injuries.

However, no one wanted to go to trial solely based on the owl theory, and Peterson instead went for what is known as an Alford Plea.

the staircase killer The murder was actually pegged on an owl at one point (Credit: Netflix)

What was the Alford Plea and where is the Staircase Killer now?

In February of 2017, when Peterson was 73-years-old, he entered an Alford Plea to the voluntary manslaughter of his late wife.

The Alford Plea is when you do not admit guilt, but acknowledge that there is enough evidence to find you guilty. As Peterson had already served eight years in prison, he was free to leave.

In a subsequent press conference, he said it was "the hardest thing I've ever done".

Kathleen's family, however, did see it as some sort of justice. At the hearing, her sister, Candace Zamperini, said to Peterson: "Alford, Schmalford, you are pleading guilty and you will be regarded as a convicted felon forever."

Peterson still lives in North Carolina, but as a convicted felon. He lives alone and wrote a book in 2019, called Behind the Staircase.