Guyard, 31, was pronounced dead shortly before midnight Saturday.
The exact cause of her death had not been determined, the Clark County, Nev., medical examiner's office told CNN Sunday.
CNN said the fatal mishap occurred during the show's finale when Guyard was being hoisted up on a wire 50 feet in the air for a fight scene with other performers.
The show has been canceled indefinitely and the company told CNN it is fully cooperating with authorities investigating the incident.
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