MESA, Ariz. -- A woman watching a brush fire in her neighborhood was struck and killed Tuesday night after her father backed up his pickup truck and ran over her, Mesa police said.

At the time, Mesa fire crews were putting out a brush fire, and the activity caught the attention of the family, police said.

Ashley Mortensen, 21, went outside to get a closer look, officers said. Her father, Ronald Mortensen, 53, decided to drive to the scene and backed up his truck, not realizing his daughter had walked behind the pickup, police said.

Ashley Mortensen was trapped under the truck until the fire department arrived, and she showed no signs of life at the scene, police said. She was taken to a nearby hospital where she was pronounced dead.

Her mother, Melissa South, was there moments after her daughter was run over.

"I just keep feeling like I need to wake up out of this dream," South said.

South said her daughter in recent days was the happiest she'd ever seen her. She had planned to get married Sept. 25. She died while running an errand for her upcoming wedding.

"She had come over to get her wedding list, and she walked out with her wedding list and went to get back in the truck," South said. "Because of where she was placed under the car, he couldn't back up or move forward, or he'd run over her again, so they had to lift the truck up."

Officers said Ronald Mortensen was not impaired, and they will not be pursuing charges.