A 22-month-old West Ashley boy was killed Thursday when he was accidentally run over by a sport-utility vehicle being driven by his father, authorities said.

Victor Ayala Jr. died of massive head trauma, Charleston County Chief Deputy Coroner Judy Koelpin said.

According to investigators, the tragic accident unfolded like this:

--The boy's father, Victor Ayala, had two vehicles in his driveway and was going to wash one of them.

--Several children, including the boy, were playing in the garage.

--Ayala started backing his SUV down the driveway, with the driver's-side door open, when his son darted out of the garage and toward him.

--Ayala reached out of the door to scoop up the child, but lost his balance and tumbled out of the SUV.

--The boy fell into the path of the driver's-side tire of the SUV, which was still in reverse, and was run over.

--The SUV, at this point without a driver and still in reverse gear, kept going across the street and struck the garage door of a neighbor's home.

The accident occurred shortly before 5 p.m. at a house on Cabrill Drive in the Grand Oaks subdivision, Charleston Police public information officer

Charles Francis said.

The Charleston Fire Department responded, and Charleston County EMS transported the child to Medical University Hospital, where he was pronounced dead.

Police put yellow crime-scene tape around the area and investigators took photographs and made notes about the distance between the father's driveway and the driveway across the street.

No charges have been filed and the investigation is ongoing, Francis said.

Nearly 50 children are injured each week as a result of vehicles backing up, and two typically die, according to data from the Centers for Disease Control and Prevention.

In most cases, a family member is behind the wheel.

In 2007, a 4-year-old Goose Creek girl who was playing in her driveway was killed when she was backed over by a pickup truck driven by her father.

Reach David W. MacDougall at macdougd@postandcourier.com or 937-5655.