Carl Dodd, a Washington, D.C., transit worker, says he has had a hole in his life since his 4-year-old daughter, Marilyn, disappeared 13 years ago.
Marilyn was gone without a trace after her mother took off during a custody battle.
"I felt like a piece of my heart had been taken away from me, not knowing if I would ever see her again," Dodd said.
On five different occasions, authorities told Dodd that they had found his daughter. But each time they were wrong.
Finally this week, pain turned to exhilaration after Dodd got a call from the U.S. Marshals Service that they had solved the oldest parental abduction case. This time they were right.
"I started feeling chills running through my body," he said. "It's about to happen."
In December, the Center for Missing and Exploited Children decided to team up with the FBI and the U.S. Marshals, who are best known for hunting down fugitives. The marshals began a painstaking investigation of every lead in the case, every friend, every relative.
"We were able to gain information in the D.C. area," said Marshal David Thomas. "They believed that she moved somewhere up the coast. A lot of addresses were pointing towards Wilmington, Del."
But Marilyn Byrd would be 17 years old now. What would a 4-year-old look like as a young adult?
The marshals relied on the center's age-enhancement technology, which estimated her growth rate and how her features would change over 13 years.
"We brought in some subtle maturity into the area of the eyes, into the area of the nose," said Glenn Miller, supervisor for the Forensic Services Unit at the National Center for Missing and Exploited Children. "These are again slow changes, very small, but we have to be conscious of that when we do the age progression."
Thomas said the result was startlingly accurate. "The picture was dead on with what she looked like," he said. "Our deputies were able to notice her right away with this photograph."
Most abducted children are eventually found. Dodd will finally get to see his daughter Monday. He is nervous.
"Thirteen years is a long time," he said. "It's like meeting a stranger. I'm hoping this is what she wants. "
And he knows just what he'll say when he sees his daughter.
"I love you," he said. "Second line, I miss you."
ABC News' Pierre Thomas reported this story for "World News Tonight."