Here's the Harrowing True Story Behind New HBO Show 'The Staircase'

HBO Max recently announced that it is developing a limited series adaptation of The Staircase, a 2004 French docu-series of the same name. Following the success of crime dramas such as Mare of Easttown, HBO's strategy to pursue twisty thrillers makes sense.

The Staircase is based on the real-life murder trial of Michael Peterson. 

Read on to find out everything we know about The Staircase and the case that started it all.

The Staircase in its original format was filmed as a documentary rather than a fictionalized version of events. Filming reportedly began as soon as Michael Peterson was convicted.

Camera crews were given access to Peterson's extended family, the courtroom, and the defense attorneys. Filming was finished by 2005, but when new developments in the case happened in 2012-2013, filmmaker Jean-Xavier de Lestrade returned with new footage, this time to Netflix.

HBO Max is taking a different approach to The Staircase, moving away from the documentary style in favor of a more dramatized version of events. Deadline announced that Colin Firth will be playing the accused Michael Peterson, and Toni Collette will play the deceased Kathleen Peterson. Rosemarie DeWitt will be playing the part of Candace Zamperini, Kathleen Peterson’s sister.

Additional cast members include Parker Posey as Freda Black, assistant district attorney and prosecutor in the Peterson case, Sophie Turner as one of Peterson's adopted daughters, and Juliette Binoche in an undisclosed role. The plot will follow "the life of Michael Peterson ... his sprawling North Carolina family, and the suspicious death of his wife, Kathleen."

In the initial court case, novelist Michael Peterson was accused of killing his wife Kathleen after she was found dead at the bottom of a staircase in their home in 2001. The battle to determine Michael's innocence — or lack thereof — spanned 16 years following Kathleen's death. Michael was the prime suspect in the case and was eventually convicted of murder.

After Michael's sentencing to life in prison without parole in 2003, he and his lawyer filed for an appeal in 2005. He was eventually able to get a retrial in 2011 when one of the witnesses in Michael's case was fired after he reportedly lied about his qualifications to be a blood splatter analyst. In 2017, Michael was released from prison after being found guilty of voluntary manslaughter.

Michael continued his career as a novelist and even self-published a book titled Behind the Staircase in 2019, giving his account of his trial, imprisonment, and life after release. He has not lived in the five-story house that he owned with Kathleen since 2004; allegedly Michael currently resides in Durham, North Carolina.

Despite his sentencing, Michael maintains his innocence, so it's up to new viewers of the story to determine for themselves whether they believe his story or the evidence at hand. 

You can watch the initial documentary The Staircase now on Netflix. The HBO Max adaptation currently has no release date.