The teen driver lost control of the pickup, causing the vehicle to roll.
Kyla died and the two boys who were passengers were flown to Children's Hospital in San Diego. They have since been released from the hospital. The driver was not seriously injured.
According to the Highway Patrol, the pickup was heading down Wheeler at 55 mph when the accident occurred.
Authorities have said that was an unsafe speed for the road and the conditions, adding it is partly for that reason the Highway Patrol is considering seeking a manslaughter charge against the youth.
Authorities said the fact the boy did not have a driver's license and was operating a vehicle on a county road is another reason.
If the Highway Patrol does seek a charge, the final decision on whether to file that charge will rest with the District Attorney's Office.
Authorities have said the teen was driving the pickup with permission from his parents, who also were in the Superstition Mountains at the time.
He said the youths in the pickup were supposed to drive from one camp to another in the area and remain off-road.
While Wheeler is a dirt road, it is considered a county road and is not an off-road area, Highway Patrol officials have said.
Highway Patrol Officer David Marrs said this morning there are no plans to pursue any charges against the parents.
He said the CHP "does not have the necessary information or evidence to support any charge that may be sought against the parents."
In regard to possible charges against the driver, Marrs said there are two key reports the Highway Patrol needs.
One is the autopsy report that will be released by a pathologist; the second involves the toxicology results, which the Highway Patrol has received.
County Sheriff's Office Sgt. Rick Macken, who heads the Coroner's Office said the toxicology results show Kyla had no alcohol or drugs in her system.
Macken said his office has done its own reports, separate from the pathologist's report, on the cause of death. He said the preliminary results are that she died of blunt impact injuries to the neck.
However, the final cause of death is dependent upon the pathologist's report.
>> Staff Writer Darren Simon can be reached at 337-4082.