10:55 AM: The Blast has obtained the emergency audio describing how Kidder was unfortunately dead when crews arrived.
Margot Kidder — best known for playing Lois Lane alongside Christopher Reeve in the "Superman" films — passed away on Sunday. She was 69.
An obituary listed on the website for the Franzen-Davis Funeral Home and Crematory in Livingston, MT reads, "Margaret Ruth 'Margot' Kidder, 69, of Livingston, Montana. The actress and activist passed away on Sunday, May 13th, 2018 at her home."
In addition to playing Lane in four "Superman" films, Kidder also appeared in a 2002 production of "The Vagina Monologues."
Kidder was romantically linked to Canadian prime minister Pierre Trudeau, Brian De Palma, Steven Spielberg, and Richard Pryor. She was married and divorced three times and one child, a daughter named Maggie.
She was diagnosed with bipolar disorder and famously had a manic episode in 1996 and disappeared for four days.
Kidder became a U.S. citizen in 2005 (she was born in Canada) and became a very outspoken political activist.