20/20

In 1981, authorities in the Houston area found a young couple who had been strangled and beaten to death. For 40 years, the victims remained nameless, joining thousands of other unsolved murders in the United States. A breakthrough in 2021 finally revealed the identity of the couple and deepened the mystery — what happened to their missing baby? David Muir reports on the decades-long hunt for answers, taking viewers inside the multistate investigation that reunited 42-year-old Holly Marie with her remaining biological family.

Exclusive interviews with Holly Marie, who reflects on meeting her long-lost family; her adoptive father, Phillip McGoldrick, whose story about Holly's unusual adoption adds a new layer of mystery to her parents' deaths; and footage of Holly's reunion with her family. "20/20" also has an exclusive interview with lead investigator Rachel Kading, along with Brent DuPre and Mindy Montford of the Texas attorney general's office, who provide critical insight into the investigation, and members of the Christ Family religious group that Holly's parents had joined. The episode includes additional interviews with members of the investigative team from Florida and Texas, who remain committed to solving the murders.