Did he do it? The Staircase gives answers. Or does it?

Colin Firth stars as author and political-wannabe Michael Peterson, opposite Toni Collette as his wife, Kathleen, in drama series The Staircase, now streaming on Showmax and based on the highly publiced real-life case.

Kathleen was found dead – or dying – at the bottom of a staircase in their home, Durham, North Carolina on 9 December 2001. In 2003, Peterson was convicted of her murder.

The eight-part limited series tells the story of before, during and after; Peterson ended up spending a decade behind bars before being granted a retrial based on new evidence. After six years of back and forth, the retrial never took place, with Peterson eventually taking an Alford plea and walking away a free man – even though he had to plead guilty to Kathleen’s murder while still maintaining his innocence. The American “justice” system can be complicated.

A documentary by the same name was made during the build-up to Michael’s trial, and the making of the documentary forms a large part of this series, which offers a multitude of details about the case, the defence, prosecutorial corruption and misconduct, inconclusive autopsy results, as well as Michael and Kathleen’s personal life.

At the time of Kathleen’s death, the couple had five grown children between them: Kathleen’s biological daughter, two daughters adopted by Michael and his ex-wife, Patty, and his and Patty’s two sons.

At the end of The Staircase, two possible scenarios of Kathleen’s death have been played out for us, and finally, a possible motive is admitted by Peterson. Will we ever know the truth? Perhaps not. As they say, two people can keep a secret as long as one of them is dead.

For the most part, Peterson’s innocence is presumed, and remember, everything can be framed the way we are required to perceive it. But here are some moments to look out for that might tip your opinion one way or the other.

Moments in The Staircase that make us think that Michael Peterson is guilty

Episode 1: A panicked 911 call from Peterson asking for help is logged. His wife is still breathing, he says. Five minutes later, in a second call, he says she is not. The EMTs claim she had been dead a lot longer than this timeframe.

At the autopsy, apparent defensive wounds are noted. Kathleen’s hyoid, the U-shaped bone of the neck that is fractured in one-third of all homicides by strangulation, is broken.

Plus of course, the husband is always the first suspect. Women “fall down the stairs” or “walk into doors” all the time. Studies have shown women are far more likely to die at the hands of someone they know. The UN reports: “Some 47 000 women and girls worldwide were killed by their intimate partners or other family members in 2020. This means that, on average, a woman or girl is killed by someone in her own family every 11 minutes.”

Following the execution of a search warrant, Peterson’s personal computer is seized, and a significant amount of male gay porn is discovered. Could Kathleen having found out about this be a motive for him to kill her? He says no, she knew about his proclivities, and that he is bisexual. There were no secrets between them.

Episode 2: The documentary filmmakers arrive on the scene, and Peterson’s story appears to falter a bit. Kathleen’s wounds but lack of skull fractures are puzzling; they don’t fit with the blunt force trauma theory.

Meanwhile, Kathleen’s uptight sister Candace (Rosemarie De Witt) believes she has found the murder weapon, a fireplace tool given as a gift to each sister one Christmas. Weird gift, but okay.

Episode 3: Peterson insists Kathleen knew he occasionally slept with men, but she’s not there to confirm or deny, is she? The filmmakers, who are French, think he’s lying, about this and everything else. Then it is revealed that, in 1985, Michael’s friend Elizabeth Ratliff also died at the bottom of a staircase in her home – a home that Michael often visited. After her death, Michael and Patty (Trini Alvarado) adopted her daughters, Martha (Odessa Young) and Margaret (Sophie Turner aka Lady Sansa).

Another woman, another staircase … what are the odds? All we need now is Ivana Trump.

It’s around this time that the crime lab working for the District Attorney report that they’ve managed to replicate Kathleen’s injuries with the blow poke (the fire tool) – but they don’t have the actual murder weapon.

Episode 4: Peterson’s lies become exposed. He claimed to have a Purple Heart from his time in Vietnam, but he does not. This will not be the first time he will be outed as a liar. And if he can lie about some things, he can lie about other things, right?

This is the episode where the squeamish should cover their eyes – Toni Collette as Kathleen dies brutally in a plausible chain of events.

In court, Peterson is found guilty and sentenced to live out the rest of his natural life in prison, without the benefit of parole.

Episode 5: Now Peterson has been imprisoned, there’s not much for the documentary makers to do except argue about whether they think he is guilty or not. Juliette Binoche plays Sophie, the editor of their series, who will become instrumental in taking up Peterson’s cause.

Episode 6: It took a while, but the next-door neighbour suddenly comes up with a new theory that could explain Kathleen’s injuries, and her lack of skull fractures.

Once again, Collette as Kathleen dies.

Episode 7: One of Peterson’s alleged lovers is murdered by another of his alleged lovers (you can’t make this up), and the cause of death is blunt force trauma to the head – no skull fractures. Kathleen’s case is no longer unique.

More of Peterson’s lies are brought to light, surrounding the adopted girls. This extended family is a mess.

Episode 8: In court for the Alford plea, Kathleen’s sister Candace makes a speech. “An innocent man doesn’t plead guilty,” she says.

In the final moments of the episode, it’s disclosed that Michael did lie about telling Kathleen about the men. She didn’t know.

“Did you kill Kathleen?” he is asked. A pause. “Kathleen’s death was an accident,” he replies. A typical psychopathic answer – that is, not an answer – to a direct question.

Before the screen fades to black, we see a close up of Peterson’s face looking into the camera, a tiny smile playing on his lips…

What do you believe really took place that night in the Peterson home when Kathleen died? Stream The Staircase to help make up your mind.