Investigators say a hoist suspended from a medical helicopter, which was carrying a nurse and patient from a Texas hiking trail, was spinning just before the nurse fell to her death.

The National Transportation Safety Board on Tuesday released its preliminary report into the April 27 accident in Austin.

The report says 46-year-old Kristin McLain secured the patient in a carrier and that the two were suspended from the helicopter when the hoist began to spin. The spin had almost stopped when the hoist operator inside the STAR Flight helicopter noticed that the nurse was riding lower than normal. McLain then fell from the hoist.

The report does not say how far she fell.

Travis County Emergency Services, which operates STAR Flight, didn't immediately return messages Tuesday.