Step-by-step courtroom classic in ‘The Staircase’

“The Staircase,” which begins tonight on the Sundance Channel and continues Mondays through the month, is an eight-part documentary about the 2001 death of businesswoman Kathleen Peterson and the ensuing trial of her writer-husband, Michael, who either found her dead at the bottom of a flight of stairs or killed her there himself.

It’s a splendid piece of cinema-verite storytelling, fascinating, thought-provoking and dramatically clear, and no less popcorn-compelling for being leisurely and long. Quite the reverse: A two-hour cut ran last July on ABC (“Dateline NBC” also ran a special), but the length -- and the sense of intimacy it creates -- is crucial to the film’s success, if not as a simple summary of fact and rumor, then as a complex work of art.

As directed by French filmmaker Jean-Xavier de Lestrade, artfully photographed by Isabelle Razavet and scored for chamber strings by Jocelyn Pook (“Eyes Wide Shut”), it’s something like a cross between Frederick Wiseman’s long-form institutional documentaries and Errol Morris’ “The Thin Blue Line,” an examination both of the workings (and the machinations) of the justice system and of the slippery nature of truth. You keep watching not only to find out what happens but also because your view of what’s happening constantly changes as new information casts old assertions in a different light.

That De Lestrade had just won a best documentary feature Oscar for “Murder on a Sunday Morning” -- about the railroading of a black teenager for the murder of a white tourist in Florida, and the public defenders who stopped it -- helped gain him remarkable access to the accused, his lawyers and (for a time) to the prosecution. “The Staircase” is a kind of upper-class variation on the earlier film, with Peterson himself noting that “American justice is very, very expensive.”

Shot in Durham, N.C., over the course of two years -- with evidentiary side trips to Germany and Texas -- “The Staircase” shows, among other things, how a high-priced defense team prepares for trial: the interviews and investigations, focus groups and expert witnesses, the creation of an alternate narrative, the assembly of charts and models, computer simulations and PowerPoint presentations, the conferences and the coaching. It regards the swarming, sensationalist media -- Court TV, which was on this story like white on rice, comes off as particularly bad -- and how strategies change in the wake of leaked stories and breaking news. It comes out first that Peterson is actively bisexual -- the prosecution suggests a motive for murder upon that shaky ground -- and then, much more remarkably, that 17 years earlier, in Germany, his neighbor died under similar circumstances and that Peterson was the last person to see her alive. (He raised Elizabeth Ratliff’s orphaned daughters as his own; they stood by him through the trial.)

De Lestrade clearly has some opinions on the way the state conducted its business, as mirrored in some of his “chapter headings” -- “A Weak Case,” “A Prosecution Trickery,” “The Prosecution’s Revenge” -- and the mere fact of the camera spending most of its time in the defense camp leads one increasingly to take Peterson’s part. But as to his guilt or innocence, the film makes no claims. It’s a study, rather, in how we fit the world to our opinions, and how one person’s coincidence can be another’s conspiracy. (Somebody here has to be wrong about Michael Peterson, but no one believes he is.) Police and prosecutors are blinkered by their own quick conclusions -- “You can’t look at that and think that it’s an accident,” says one of the bloody stairwell where Kathleen died, though defense experts can’t see it as anything but -- and by their world view. (To some, Peterson’s solicitation of gay sex meant, ipso facto, that “he was not a happily married man,” and the prosecution portrayed him as a kind of pervert.) Some family members see him through a mist of love, others through a flame of hate.

The viewer faces a similar situation: Just how you see “The Staircase” will have something to do with how you already feel about Southern cops and Northern lawyers, and what you make of Peterson himself, with his professorial pipe and habit of self-dramatization -- even his stoicism can seem put on, whether or not it is. When he addresses a crowd of reporters outside the courthouse in the cadences of bad poetry -- “Kathleen was my life / I whispered her name in my heart a thousand times / She is there / But I can’t stop crying” -- one may well ask, “Who’s he kidding?” Listening to his 911 call, one wonders, is this the voice of concerned panic, or is this good acting, or is it the actually panicked voice of a man who has just committed murder? And it’s impossible to say.

*

‘The Staircase’

Where: Sundance Channel

When: 9 p.m. Mondays

Ratings: TV-14 (may be unsuitable for children under the age of 14, with advisory for adult content and language)

Michael Peterson...Self

Defense attorney David Rudolf...Self

District attorney Jim Hardin ...Self

Producer, Denis Poncet. Director, Jean-Xavier de Lestrade.