(AP) — The FBI has reopened its investigation of the 1964 kidnapping from a Chicago hospital of an infant who was seemingly reunited with his parents more than a year later.

That’s what everyone thought until that boy — now a 49-year-old Henderson, Nev., college administrator — got his and his parents’ DNA tested this year. Paul Fronczak says the tests showed he’s not his parents’ biological son.

Fronczak told the Chicago Sun-Times in June they got their DNA tested because he long wondered why he didn’t resemble his parents, Chester and Dora Fronczak.

The couple’s son was abducted from Michael Reese Hospital. The case seemed to end happily when they were reunited with a boy resembling theirs who was found abandoned in New Jersey.

The case was reopened Wednesday.