Sheriff's deputies were called to the scene. A few hours later, her still relatively intact body was discovered several hundred feet away from the arm bones, in a grove of brushy salt cedar.
While most of her tissue was gone, nearly all of her bones were intact, held together by blackened, mummified skin. A black widow spider had spun a web inside her skull.
That her body was relatively intact after supposedly lying in the desert for nearly two months fueled speculation that she had been hidden elsewhere and moved only recently.
"Frankly, it was kind of surprising to me there hadn't been more loss of tissue from animals," says County Attorney Jack Williams, who saw the remains where they were found.
Valenzuela and other searchers say they had been within 20 feet of where she was found during their extensive searches and never saw or smelled her body. On the day she was found, a DPS homicide technician said a potent odor was apparent from 50 feet.
Medical examiners say decomposition and odor vary with each case and are dependent on many factors including sunlight, humidity, rainfall, the type of animals present and the adjacent soil. Stephanie's body had clearly been at the site for at least some time, because her body fluids had drained onto different spots on the ground, leaving two greasy, odorous stains.
In line with the rest of the slipshod investigation, analysis of the site amounted to little more than a cursory review by DPS homicide technicians, who swept the area with metal detectors searching for bullets and knives. None were found. DPS also conducted tests to determine whether she had been sexually assaulted. They turned out negative.
Mack says the DPS technicians told him or a member of his staff that the body had been there at least two or three weeks. But Pat Wertheim, one of the DPS technicians who examined the body, says no such determination was made.
"As far as determining how long the body was there, we don't do that," he says.
Wertheim added that his "gut feeling" was that "it had been there quite a while."
Deputies took a few photographs of the site and the body, before the remains were transported to Tucson for an autopsy.
Valenzuela contends deputies should have taken extensive soil samples from the area and compared those with samples taken from Goodrum's vehicles, trailers and clothes. No samples were taken.
Moments before finding her body, a deputy discovered a mud-clad pair of black, high-top Spalding tennis shoes on the bank of the normally dry San Simon River. Goodrum, who was unable to recall what else Stephanie was wearing that night, had repeatedly told investigators he was certain that she had been wearing black, high-top athletic shoes.
"Both shoes were placed there, right together, and were up where the river water could not get to them," sheriff's investigator Morris would write in a report that appears not to have been prepared immediately. Valenzuela says it wasn't in the investigative file turned over to him a month after the body was found.
Deputies took no photos of the shoes in the location they were found. The shoes were taken to Matlock for identification, who said they could have been Stephanie's.
Other than that cursory identification, however, no analysis was performed. Oddly, one shoe was missing all its shoelaces, and the laces on the other shoe appeared to have been cut.
Morris' report was not only notable for being late, it also omitted key facts. The report stated Stephanie's body was located "approximately 216 feet east of the roadway" that ran parallel to the San Simon River.
But Morris' report does not mention another Jeep trail that leads directly to the site where Stephanie was found.
That Jeep trail ended at a turnaround area no more than 20 feet from where her body was found. The proximity of the trail to the location of her body suggests at least the possibility that Stephanie's body was driven to the site, and then dumped.
When asked about the omission of the road from Morris' report, Mack simply shrugged his shoulders.
Deputies also found a pair of black sweat pants in the riverbed, partially covered by weeds and trash. No tests were done on the pants to determine if they were Stephanie's.
An autopsy on Stephanie's body was conducted two days later in Tucson by forensic pathologist John D. Howard. Mack attended the examination.
The autopsy revealed that a crucial neck bone, which sometimes indicates strangulation if displaced, had fallen apart.
In young people, the cartilage holding the hyoid bone in place often quickly deteriorates after death. There was no other damage to adjacent neck bones, making it impossible for Howard to say with certainty she was strangled.