A man long believed dead, the victim of a notorious serial killer, stepped off a Greyhound bus in southern Alabama this week and hugged the brother and sister who couldn’t believe their eyes.

“He’s back,” proclaimed Theresa Hasselberg, who had not seen her brother in more than three decades.

For 34 years, the family of Harold Wayne Lovell was convinced he was among those murdered by infamous serial killer John Wayne Gacy, who killed 33 young men and boys in the 1970s.

Lovell had disappeared from his home near Chicago in May 1977. Then a troubled 19-year-old, thin with sandy blond hair, Lovell had told his family he was looking for a construction job. But he never returned.

His brother and sister feared that Lovell had met Gacy when both worked in the sprawling suburb of Aurora, Ill. And when Lovell vanished around the time of Gacy’s killing spree, they figured he must have been among Gacy’s unidentified victims, most of them buried under his home just outside Chicago.

In fact, Lovell told ABC affiliate WDHN, he did meet Gacy: “I did a couple of days of yard work with him. That was it.”

The family may never have been reunited had the Gacy story not re-surfaced earlier this month. Cook County, Ill., Sheriff Tom Dart publicly asked all family members of possible Gacy victims to come forward with genetic profiles to help identify eight young men who were never positively named.

The murders took place between 1972 and 1978, an era before widespread DNA testing. Skeletal remains of the eight un-identified victims were exhumed earlier this year.

More than 120 families responded, including Lovell’s younger sister, Hasselberg, and a brother, Tim Lovell.

“Because of the quality of these leads, what we thought was going to just be a roll of the dice has turned into some very strong possibilities for identifying these victims from DNA,” Dart told ABC News.

Instead of a sad but final confirmation regarding Lovell’s fate, his family discovered something beyond their wildest imaginations: a police booking photo showing their brother was alive in south Florida.

Dart said his detectives tracked down Lovell through the police mug shot after his family contacted the sheriff’s office.

Lovell told his family he had $56 in his pocket when he ran away from home after arguing with his mother and step-father. His mother died in 2001.

In the last two days, the three siblings have tried to catch up on the last 34 years.

“A lot of crying and hugging,” said sister Hasselberg.

Lovell, now 53, spent most of them in Florida, working in shipbuilding and landscaping. He also had a few scrapes with police, leading to the booking photo that eventually reunited Lovell with his long-lost siblings.

Other families are waiting to clear up their own mysteries; at least seven of them have submitted DNA samples that Cook County, Ill., sheriff’s investigators will check against genetic material from the unidentified victims.