A character’s death usually spells the end for them in a horror film, but in André Øvredal’s newest thriller The Autopsy of Jane Doe, it’s just the beginning.

In The Autopsy of Jane Doe, things go to hell when a Jane Doe (Olwen Kelly) is brought late at night to estranged father-son coroners Tommy (Brian Cox) and Austin (Emile Hirsch). To survive and overcome personal distance, the two try to rid themselves of the malevolent Jane Doe, who clearly has some supernatural shit going on.

During production, Øvredal had the unenviable task of convincing audiences that a perfectly living actress, Olwen Kelly, was both dead and an active, patient force of nature, waiting to make her killing stroke.

“You want to make her dead, but still need a sense of life to her,” he told Inverse. “You need to be intrigued by her eyes. She’s staring at us with slightly different looks as the film progresses.”

It was a balancing act, as Olwen couldn’t express a wide range of emotion no matter what unfolded around her, or because of her. Øvredal credits Olwen’s intense yoga training, which she used to minimize her breathing. The director recalls sitting on shots for “minutes at a time,” barely saw any movement from his “dead” star. “Owlen had everything we were looking for in Jane: vulnerability, a sense there’s something behind her,” he said. “In the beginning she’s a mystery, and then you broaden the audience’s understanding along with Austin and Tommy’s.”

For nearly the entire film, Olwen lies prone on an examining table, and as the story progressed, the director shot her from different angles to indicate the changes. “When they discover she’s a victim of horrific events, you have to shoot her in a way that makes her look and feel vulnerable,” Øvredal said. “As the movie progresses, it becomes more important to portray her in a different way.”

The director added that studying how real autopsies are performed also helped, as it was necessary to use standard medical operation procedures that worked on camera. “We make sure we put the camera [to make her] part of a trio on screen. It gave her a sense of cold distance and getting to know her at the same time, and close-ups that were the equivalent of Bryan and Emile’s.”

While there was a prosthetic doll that was sometimes used, it was necessary for the small-budget production to have the real deal as much as possible. The actress also wore attachments that were physically painful, sometimes for hours “and patiently so.”

“If it hadn’t been for Olwen it wouldn’t be anywhere near [as good] a movie,” says Øvredal. “That’s the thing I fell in love with. This isn’t teenagers running around. This is a family with a missing part, the subtle dynamics of keeping things from each other and trying to get closer. I just fell in love with that dynamic.”

The Autopsy of Jane Doe will be released on VOD on December 20 and select cities on December 21.

Photos via IFC Midnight