Watch An American Murder Mystery: The Staircase

The defense unveils what they claim is a long sought-after piece of evidence. The prosecution is caught off guard. Then, bombshell revelations about an expert witness threaten to unravel the entire case and give Michael Peterson a shot at freedom.

Investigators are stunned to discover that sixteen years ago, Michael Peterson's good friend Liz Ratliff also died at the bottom of a staircase, lying in a pool of blood. The trial begins and experts battle over the interpretation of blood spatter.

Investigators discover novelist Michael Peterson clutching his dead wife Kathleen, in a pool of blood at the bottom of their back staircase. Michael insists that her death is the result of a tragic fall, but investigators believe otherwise.