The report by the Mohave County Sheriff's Department cited the 9-year-old's father, who saw her "drop the gun to the ground." Another instructor at the Bullets and Burgers range at Last Chance in White Sands, Ariz., said the recoil sent the weapon, still spraying bullets, straight up into the air.
The family did not realize immediately that Charles Vacca, 39, the instructor, had been hit in the head by the gunfire. They were concerned that their daughter was hurt.
The New Jersey residents made a trip to the gun range during a vacation in Las Vegas. The report said they took their two children on a monster truck ride at Last Chance before heading to the property's gun range.
The father took at turn at the mini Uni9mm, an Uzi-style weapon, before his daughter tried it. Vacca first had her fire a few single shots and then switched the weapon to automatic fire.
The spray of bullets "crossed the path where Charles had his head," another instructor, Ross Miller, told investigators. Vacca died shortly after being airlifted to University Medical Center in Las Vegas.
Once the parents realized what had happened, they took their children to a nearby restaurant, the report said. They refused to allow police to interview the girl or her brother, although the mother turned over video from her cellphone camera to investigators.