Tina Anderson was 12 when she vanished from a Pioneer Day celebration at Alameda Park in Pocatello, Idaho, on July 22, 1978. She and her friend, 15-year-old Patricia Patsy Campbell, were last seen that day; Tina had been expected at a babysitting job across the street from the park but never arrived. The two girls remained missing until hunters discovered their remains in October 1981 in a remote area of Oneida County, about 60 miles from Pocatello.

Investigators recovered .22-caliber bullet casings at the scene, and both girls were determined to have been shot to death. The case was ruled a homicide, but no arrests were ever made. The recovery site was excavated again in 2007, yielding new evidence described as vital to prosecuting a group of suspects. A witness reported seeing the girls with a young man in a hooded blue sweatshirt who wore a large ring on the day they disappeared, but no public identification of suspects has been released.

Anyone who knew Tina or Patsy, or who remembers the Pioneer Day celebration or the area around Alameda Park and Oneida County in 1978, is asked to come forward with information.