Then, days before Fisch was supposed to see court records revealing details about his birth mother, he died unexpectedly of a blood clot. But Fisch's children and widow Randi Fisch, determined to continue Alan's search and help Fronczak with his, agreed to meet with Fronczak.
"All four kids at the same time said they wanted to honor Alan's memory and finish this," Randi Fisch told Fronczak in a joint-interview with Barbara Walters. "He was so excited to meet you."
The next step was tracking down Alan Fisch's birth mother's name, which the family was able to do with "20/20's" help. If she is found, she would be Fronczak's closest relative revealed thus far.
Fronczak's hope is that every clue brings a tragic mystery closer to being solved.
"I'm really, really a hopeful guy," Fronczak said. "I still think we're going to solve both these mysteries. ... It's going to happen."
ABC News anchor Barbara Walters and chief investigative correspondent Brian Ross are investigating the case. Do you have any tips on this case? Click here to send them to ABC News.