Jackie was last seen walking with her older sister, Cynthia Leslie, on July 31, 1974 in their hometown of Mesa, Arizona. The sisters were headed to a friend's home that was located three blocks away from their own residence in the Desert Shores Mobile Home Park. They were last seen walking down Baseline Road near Power Road.

The girls told their mother that they were scheduled to babysit, but she learned afterwards that they planned to attend a party. Their father asked Cynthia to avoid an unidentified teenage boy, but she may have wanted to meet the individual during the evening. Cynthia and Jackie never returned home and have not been heard from again. They left all of their personal belongings behind inside their residence. Jackie was carrying a white hairbrush at the time of her disappearance.

The girls' father died several months after they disappeared. Their family relocated to the trailer park to allow him to be closer to the local hospital, as he had been diagnosed with cancer earlier in 1974. Cynthia and Jackie's mother said that they were close to their father and never would have left him while he was ill. The girls' mother remarried after their father's death. She moved to Kingman, Arizona in 1999 to be closer to her oldest daughter, who resides in Nevada. Foul play is suspected in the sisters' cases, but little evidence is available.