Mónica Marie Zorrilla Parker Posey will star alongside Colin Firth, Toni Collette, Juliette Binoche and Rosemarie DeWitt in the HBO Max limited series “The Staircase.”The eight-parter is based on the docuseries of the same name and various books and reports on the Michael Peterson (Firth) case. Peterson was accused of murdering his wife, Kathleen (Collette), in 2001.