The cases that haunt me most are local ones. Mary Ann Verdecchia, who was almost 10 years old when she disappeared in 1962. She went into the Martinique Apartments and was never seen again. The story was huge for the time, all over the 3 local broadcast TV stations newscasts, in the papers and on local radio. We've got that big 50,000 watt clear channel KDKA and you could get that clear down in Alabama at night. I was the same age as Mary Ann; it was a big shock that a kid could just disappear. It wasn't until I was older that I learned that an adult, Marcella Krulce, disappeared from the same building in 1959. Now either that building was in the Twilight Zone or a very weird serial killer/killers lived there. Or so it would seem.
Cherrie Mahan, who got off the school bus at the end of her own lane and was never seen again. Carol Jursik, a serious athlete murdered on her way home from a long run. She had stopped late at night to buy groceries and never made it home. A huge search began when she was reported missing. It took a few days for a neighbor to find the sack of groceries, which was in a neighboring driveway and hadn't even spilled. A tip directed police to a local park, where her body was found. The case was never officially solved, although there was speculation that she could have been the victim of a serial killer who was discovered years later when he tried to rape the wife of a state policeman. He may have preyed on women for years.
Brian Shaffer, Maura Murray, and the Springfield missing women would make the rest of my list.