Mary Day was a 13-year-old girl from Seaside, California, who disappeared in 1981. Her parents claimed she ran away, while investigators were determined to prove that she was murdered. In 2003, twenty-two years after her disappearance, a woman came forward claiming to be the runaway Mary Day. However, she had almost no memories of her childhood, especially from when she was 13 or younger. So…was Mary Day murdered, or did she really run away and return 22 years later?

Source:

https://www.cbsnews.com/news/mary-day-suspected-murder-victim-back-dead-dna-48-hours/