“The Staircase” centers on the real-life death of Kathleen Peterson in 2001; no one has ever been definitively proven to have killed her, and the case remains disputed. Michael Peterson, her husband, was convicted of murder in 2003, but that conviction was later vacated, and in 2017 he entered an Alford plea to voluntary manslaughter, meaning he accepted a conviction while maintaining his claim of innocence.

What happened legally

• In 2003, a North Carolina jury found Michael Peterson guilty of murdering Kathleen, who was found at the bottom of the staircase in their Durham home, and he received a life sentence.
• Years later, problems with key prosecution expert testimony led a judge to order a new trial, and Peterson was released on bond while the case was pending.
• In 2017, instead of going through a new full trial, Peterson entered an Alford plea to voluntary manslaughter: legally accepting the state had enough evidence to convict, but still asserting that he did not kill Kathleen.

So “who did it”?

• Because of the Alford plea and the contested evidence, there is no legal finding now that clearly resolves “who did it” in the sense of a final, uncontested murder verdict.
• Many people remain divided: some believe Michael killed Kathleen, others think it was a tragic fall, and some favor alternative explanations like the “owl theory,” but none of these has been conclusively proven in court.