MILWAUKIE, Ore. – A Milwaukie mother accidentally hit her 9-year-old daughter with her car in a freak accident in the family driveway Monday night, authorities said.

The girl died a short time later.

Monica Weatherby told deputies she went out to move the car and her two daughters, 9-year-old Ariana Miles and 7-year-old Alahna Miles, came up and opened the passenger door to talk to her. She told the girls to get away from the car since she was getting ready to move it, and they closed the door.

As she started to back up, something on the floorboard caught the accelerator pedal, said Detective Jeffrey Green, spokesman for the Clackamas County Sheriff's Office.

Weatherby said the car started spinning to the right and the passenger door flew open, hitting both her daughters. The car stopped after hitting a utility pole.

Ariana Miles was transported to Oregon Health & Science University Hospital, where she died of internal injuries from being hit by the car door, Green said.

Weatherby was not injured.

Investigators found a small stereo face plate on the car’s floorboard on the driver’s side, according to Green.

The Multnomah County Medical Examiner ruled the death accidental. No charges were expected.