Her family members were focused on the girl because they thought she was injured by the gun's recoil and didn't immediately realize instructor Charles Vacca had been shot until one of his colleagues ran over to him.
The family, whose hometown hasn't been revealed by investigators, had taken a shuttle on Aug. 25 from Las Vegas about 60 miles south to the Last Stop range in White Hills, Arizona.
The report did not say why the family had gone to the range or why they let the girl handle the Uzi.
After arriving, the girl, her parents, sister and brother took a monster truck ride before heading out to the shooting range.
The girl's father was the first one in the party to handle a weapon. After he fired shots, Vacca instructed the girl on how to shoot the gun, showed her a shooting stance, and helped her fire a few rounds.
Then, he stepped back and let her hold the Uzi by herself. She fired the gun, and its recoil wrenched the Uzi upward, killing Vacca with a shot to the head, according to the report.
The girl dropped the Uzi, and Vacca fell to the ground. The girl ran toward her family, who huddled around her as she held her shoulder. Another instructor rushed over to help to Vacca. The other children were then taken away from the range, according to the report.
The report describes the family as shaken by the accident.
Prosecutors are not filing charges in the case. Arizona's workplace safety agency is investigating the shooting-range death.
County prosecutors say the instructor was probably the most criminally negligent person involved in the accident for having allowed the child to hold the gun without enough training. They also said the parents and child weren't criminally culpable.
The girl's mother had video-recorded the accident on her phone.
"All right, go ahead and give me one shot," Vacca tells the girl in the video. He then cheers when she fires one round at the target.
"All right full auto," Vacca says. The video, which does not show the actual incident, ends with a series of shots being heard.
The shooting set off a powerful debate over youngsters and guns, with many people wondering what sort of parents would let a child handle a submachine gun.
Sam Scarmardo, the range's operator, has said the parents had signed waivers saying they understood the rules and were standing nearby when the accident occurred. He also had said he never had a safety problem before at the range and said his policy of allowing children 8 and older to fire guns under adult supervision and an instructor's watchful eye is standard industry practice, though he noted his policies are under review.
Vacca's ex-wife and children said last week that they harbored no ill feelings toward the girl or her family. Instead, they feel sorry for the child and want to comfort her.