Colin Firth stars in suspenseful murder trial saga The Staircase

A picture-perfect family sit around the dinner table. Five adult children — from three different sets of parents — are flanked by a husband and wife. A chalice, referred to as “the loving cup”, is passed around and they make toasts of gratitude. “There are not many families like us,” the husband says proudly, “we stick together and we love each other.” Three months later, the wife will be dead and the husband will be on trial for murder.

HBO Max’s intense eight-part mini-series The Staircase (airing in the UK on Sky Atlantic) combines true-crime thrills with an account of how a tight-knit family unravels in the midst of a crisis. A dramatisation of a 2004 docu-series of the same name, it leads up to and follows the aftermath of the high-profile death of Kathleen Peterson, wife of the novelist Michael Peterson.

In December 2001, Kathleen was found barely conscious at the bottom of the stairs by her husband in their North Carolina home. She died within minutes as a result of severe cranial lacerations, wounds deemed more consistent with an assault than a fall. Michael is immediately identified at the scene as a prime suspect in a potential murder.

Peterson is played by Colin Firth, a restrained, stately actor with whom it’s difficult to reconcile the idea of hot-blooded uxoricide. But that’s precisely the point. Outwardly, Peterson, the respectable family man with small-scale political ambitions, also seems incapable of the crime. But with every scene Firth sheds more of his signature poise and a different Peterson begins to emerge, one with an aptitude for manipulation and with clear motivations for being a single man again.

As the evidence against him mounts, Peterson posits that he’s being set-up by the police in retaliation for having been critical of the local DA while on the campaign trail. He hires a notoriously vulpine lawyer (the pleasingly ubiquitous Michael Stuhlbarg) to defend him, who assembles a team of forensics experts to come up with alternative analysis. One haunting sequence seamlessly intercuts scenes of them moving around the house trying to compose a credible, exonerating narrative with flashbacks of Michael and Kathleen (Toni Colette) hosting a fundraiser gala just weeks earlier.

Those already familiar with the story might not share in the suspense, but writers Antonio Campos and Maggie Cohn go beyond the lurid, macabre details of the crime itself. Some of the most engrossing moments in The Staircase are those situated along faultlines between the step-siblings.

While son Todd (Patrick Schwarzenegger) is unfailingly supportive of his father, Kathleen’s sole biological child Caitlin (Olivia DeJonge) knows that only she can see the blood that has indelibly stained the stairwell as her own. Eventually she realises that she can’t relate to her closest relatives, and finds herself cut off when she starts voicing suspicions. “Family is all we got,” Michael reiterates after Caitlin leaves home under lawyer supervision. This time the words carry a rather more threatening resonance.

★★★★☆

Episodes 1-3 on Sky Atlantic and NOW from May 5 at 9pm, and HBO Max in the US; new episodes released weekly