On Wednesday evening in New York City, Colin Firth and the cast of HBO’s “The Staircase” celebrated its premiere at the Museum of Modern Art.

Created by Antonio Campos with showrunner Maggie Cohn, “The Staircase” marks HBO’s turn at the true crime story of Kathleen Peterson, who was found dead at the bottom of her staircase in 2001. 

The story of what followed and came before — her husband Michael Peterson’s indictment and trial, unearthed secrets, treatment by prosecutors and twisting family drama — was first the subject of a 2004 documentary miniseries, then republished and given new episodes by Netflix, and now fictionalized in HBO’s limited series led by Firth and Toni Collette.

“I think about Truman Capote and ‘In Cold Blood,’ which was itself a first of its kind,” Parker Posey, who plays the prosecuting attorney Freda Black in the series, told Variety at the premiere. “There used to be a boundary with telling stories about crime and those affected by it, but now we want to know what makes them tick.”

“If you think about court cases at that time — the Menendez brothers, O.J. Simpson — court television became a new form of storytelling,” she continued. “And if we’re going to ask when crime becomes entertainment, it starts the second it’s on television.”

To that degree, Campos and Cohn have cover for their own exploits into the Petersons’ story. As his life and family were crumbling in the aftermath of Kathleen’s death, Peterson invited the French filmmaker Jean-Xavier de Lestrade to document his trial in an effort to rebalance — he thought — unfair treatment by the prosecution.

The 2004 documentary which followed — defined by its twists, shocking evidence reveals and slow-burning tone — helped to shape a genre of true crime storytelling which now overruns streaming television. It also gave permission for audiences and television producers to stride the ethical line between death and entertainment in true crime.

“We include the documentarians and the making of their documentary in our series,” showrunner, writer and executive producer Cohn explained. “They’re our Greek chorus, a storytelling device. They allow us to comment on ourselves as we’re creating the story.”

“The reason people are interested in true crime is the desire to control our outcomes,” she continued. “It’s a way to overcome the entropy that affects us, the chaos that enters any organized system. But we’re trying to become comfortable with living in the grey areas here.”

Michael Peterson was not at the premiere on Tuesday evening, and Firth — for what it’s worth — declined any interviews about the show. Collette, filming overseas, was also not in attendance.

“There was not a significant relationship with Peterson,” Cohn revealed about the series’ making. “There’s always this liminal space between the primary sources and my writing. You talk to as many people as you can, but you quickly realize everyone has their own version of the truth.”

So, what’s HBO’s version? For one thing, the series strives to give Kathleen a full character, as the overshadowing of her death by her husband’s trial was an equal tragedy in this story.

“For me, that’s what made me feel more confident about signing on, because I did have some qualms about it,” Rosemarie DeWitt, who plays Kathleen’s sister Candace, said “I couldn’t wait to work with Antonio, but the ethics of retelling the story and traumatizing the family again were difficult.”

In a strange, circular kind of way, the reality of ethical discomfort — of our obsession with solving other people’s crimes on TV — is itself a character in this show.

“For us, this was the Escher staircase of true crime,” Campos said at the premiere, without irony. “When you’re going up one staircase, you don’t — you can’t — see the whole picture,” he said. 

“The act of creating this show was my own journey into discovering how I felt about Michael Peterson’s guilt or innocence,” Campos continued. “And I’ll say, I came into production with a firm perspective and came out with a different opinion entirely.”

Could Campos share his judgement?

“Absolutely not.”