The indie filmmaker Lynn Shelton has sadly passed away at age 54 on Friday, May 15. According to a statement by Shelton’s representatives, the filmmaker died of a previously unidentified blood disorder.

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Shelton was an acclaimed director, writer, producer, actor, and editor whose naturalistic work helped make her one of the leading voices of American independent film, popularizing the “mumblecore” genre. She’s probably best known for her work on “Humpday,” “Your Sister’s Sister,” “Outside In,” and last year’s “Sword of Trust.” Shelton also worked extensively on television, helming four episodes of Hulu’s “Little Fires Everywhere,” as well as episodes of “Master of None,” “The Morning Show,” “Fresh of the Boat” and “GLOW.”

Shelton’s worked often combined improvisatory dialogue and comedy with stories that centered around empathy. Her last feature, “Sword of Trust” premiered at SXSW last year and told the story of a pawnshop owner who comes into possession of a sword that could prove the South actually won the Civil War. Though poking fun at conspiracy theorists, Shelton managed to make the audience connect emotionally to the characters.

IndieWire received a statement from Shelton’s creative and romantic partner, Marc Maron, whom she directed in “Sword of Trust,” “GLOW,” and the comedy special “Marc Maron: End Times Fun.” Maron wrote ” I loved her very much as I know many of you did as well. It’s devastating. I am leveled, heartbroken and in complete shock and don’t really know how to move forward in this moment. I needed you all to know. I don’t know some of you. Some I do. I’m just trying to let the people who were important to her know. She was a beautiful, kind, loving, charismatic artist. Her spirit was pure joy. She made me happy. I made her happy. We were happy. I made her laugh all the time. We laughed a lot. We were starting a life together. I really can’t believe what is happening. This is a horrendous, sad loss.”

READ MORE: Marc Maron & Lynn Shelton Are Co-Writing A New “Domestic Dramedy” Film

Lynn Shelton is survived by her son Milo Seal, her husband of many years Kevin Seal, her parents Wendy and Alan Roedell, and David “Mac” Shelton and Frauke Rynd. She is also survived by her brothers David Shelton, Robert Rynd and sister Tanya Rynd, as well as Maron, with whom she spent the last year of her life.