The family of Robert Hutton, 62, reported him missing in 1972 after he told his mother he was traveling from New York City to California, WGN-TV, Chicago, reported Friday.
Hutton would have passed through the Chicago area during the time serial killer Gacy was luring boys and young men to his home to torture and kill them.
Several of Gacy's victims remain unidentified and Hutton's family notified the Cook County Sheriff's office of their concerns he may have been one of the victims.
Detective Jason Moran tracked Hutton in April to Stevensville, Mont., and he was reunited with his father after 41 years, the Chicago Tribune reported.
"I sensed a little bit of regret when I was speaking to him," Moran said of Hutton. "He said he just got caught up in the '70s lifestyle, and after years went by he became embarrassed he hadn't had contact with his family and that made it easier to dismiss them."
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