Danielle Petratos pulled the old photo out every now and then, wondering where her father had gone - and why.
It was the only reminder the 42-year-old Manhasset resident had that the man was once part of her life, cradling her in his arms when she was just a toddler. She was too young then to remember the moment and too old now to harbor any real hope of seeing him again.
But her life would change in July, when she logged onto her Facebook account for the first time in months and found a message from John Watson, her long-lost father.
"I thought, 'This can't be real,' " she said this week from her living room. "I just reread it over and over again. I wondered my whole life where he was, and this was just dropped in my lap."
It had been 39 years since she had seen or spoken to him, ever since the Vietnam War veteran admittedly walked away from his wife and their 3-year-old daughter, ravaged by post-traumatic stress disorder. Psychiatrists then knew far less about treating veterans, he said, and he found therapy useless. Alcohol and Valium became his escapes.
"I just wanted to run away," Watson, 64, said from his home in Pittsfield, Mass. "But I don't try to make any excuses for what I did. . . . It was wrong."
More Vietnam veterans tended to leave their families than those in the general population because of the stresses of war, the prevalence of PTSD, the tumult of the era and an "unfriendly, rejecting, hostile population" that greeted returning warriors, said Dr. Ganesan Krishnamoorthy, a psychiatrist and program manager of the Northport VA Medical Center's PTSD unit.
"All these things disrupt the person's smooth flow back into family life," he said.
As Watson grew older, he said he spent many years searching for his daughter. But he said it was only when he found peace through studying Buddhism in recent years that he felt emotionally ready for a reunion. And advances in technology and the Internet age aided his search.
After several efforts to find her came up empty, Watson was beginning to despair when he received an e-mail with her name this summer from a genealogy site. "It was a miracle," he said.
Genealogy experts say the proliferation of online databases, phone directories, records and social networking sites have made finding lost relatives far easier. "Years ago, it was almost impossible to do," said Walter Kehoe, the president of the Computer Genealogy Society of Long Island.
After Watson found Petratos' profile on Facebook, he spent hours working on his initial note - more than 20 drafts in all. He wanted badly to reconnect, but he also knew she might feel anger and resentment.
Petratos proceeded cautiously, too: She took a few days to think about how to respond, and then she started by asking personal questions.
When she was satisfied with the answers, and he sent her some pictures of her and her family when she was a baby, she was convinced she had found her dad. She had questions, and he tried his best to answer them.
What followed was a whirlwind of instant messages, all-night phone calls and a face-to-face meeting in August. Now the two see each other a couple of times a month, and they share matching tattoos of a Buddhist eternity knot that says "Daddy" and "Dede," his nickname for her when she was a baby. Petratos' own mother has not been involved in the reunion.
Petratos has developed a new understanding of her dad: a retiree who volunteers at a veterans outreach center, an ecstatic new grandfather to her four children and a caring father who still feels remorse for abandoning his child.
"I chose to forgive him," Petratos said. "All I can do is judge him by what I see now. You can't make up for everything, but you can try."