The Staircase: A Complete Breakdown of the Peterson Family

Besides Kathleen, Michael Peterson is the only person who knows what went on the night of his wife's death. He has two sons from his first marriage to Patricia Peterson: Clayton and Todd. After his friend Elizabeth Ratliff passed away (more on her later), he also adopted her two daughters, Margaret and Martha.

Following his conviction, Michael served eight years in prison. In 2010, the defence uncovered forensic incompetence in his case, which granted him a retrial hearing, during which he was put under house arrest. His defence lawyer David Rudolf eventually helped Michael submit an Alford plea for manslaughter, which means that Michael maintains his innocence but will be legally considered a felon.

Before her death, Kathleen was a successful businesswoman, serving as an executive at Nortel Networks. Before tying the knot with Peter, she was married to physicist Fred Atwater, with whom she had her daughter Caitlin. According to friends and family, her marriage with Michael appeared to be a happy one.

In 2001, Kathleen was found dead at the bottom of the staircase in her Durham, NC, mansion. To this day, Michael says that she died from a tragic fall down the stairs. But investigators found deep lacerations on her head that seemed to indicate otherwise. Among other factors, Kathleen's $1.4 million insurance policy led to suspicions of foul play.

Michael's first wife, Patricia, had two children with him: Clayton and Todd. For several years, they lived together in Germany. There, she taught elementary school children for the Department of Defence for more than 30 years. Although they are no longer together, Patricia maintains that Michael did not murder Kathleen Peterson or Elizabeth Ratliff. In the documentary, you can occasionally see her sitting on his side with their children during his legal battle. Now retired, Patricia resides in Durham.

Caitlin is Kathleen's biological daughter with Fred Atwater. At the time her mother died, Caitlin was a student at Cornell University. Following her mother's death, she told the press, "My mother and Mike had an absolutely loving relationship and there is no way that either of them would ever wish any sort of harm on the other one." After seeing autopsy pictures and learning about Michael's affairs with men, however, she became a key witness on the prosecution's side. Her aunts Lori and Candace also believe that Michael murdered their sister.

Caitlin later sued her stepfather in a wrongful death lawsuit and was awarded $25 million in damages. Caitlin is not likely to collect any significant amount from Michael since he's indigent, but her lawyer explained that the point of the lawsuit was so that Michael would not be able to profit from the case.

Now going by her married name Caitlin Clark, she is the mother of twins and lives in Northern Virginia with her family.

Clayton is one of Michael's sons from his first marriage. Like his brother and adoptive sisters, he believes that his father is innocent. He lives in Baltimore and has two children.

Todd is Clayton's biological brother, and like his siblings, he believes that his father did not kill his stepmother. According to his father's lawyer, he lives in Tennessee.

Michael adopted Margaret (far left) and Martha (middle) after their mother, Elizabeth Ratliff, passed away in Germany from what was thought to be a cerebral hemorrhage. Like Kathleen, Elizabeth was found at the bottom of a staircase with lacerations on the back of her head, with Michael being the last person to see her alive. Margaret and her sister Martha immediately took to Kathleen, and they refer to her as their mother in the series. Like her sister and adoptive brothers, Margaret is convinced that her father is innocent.

A graduate from Columbia College in Chicago, she now resides in California and goes by her married name, Margaret Blakemore. According to IMDb, she works in the film industry and has credits as an actress, production manager, and assistant director.

Martha (left) is Michael's other adopted daughter and Margaret's biological sister. In the documentary, she indicates that she is firmly on her adoptive father's side. She also said that she experienced deep anxiety from the trial. "I used to suffer a lot from really bad nightmares; I used to have really bad panic attacks in public spaces because of being in the trial," she admitted. She now lives in Colourado.