Gene O'Donnell said his drawing looks like a young man in another image that investigators took from Jose Ramos, a New York Post exclusive reported.
Ramos was the main suspect in the disappearance of Etan, who was six when he went missing from a Soho street in 1979.
Ramos, who was declared responsible for Etan's death in a civil case, has never been criminally prosecuted, and last year, another man, Pedro Hernandez, confessed last year to strangling the boy.
O'Donnell said he was asked to create the age-adjusted drawing in 1990, and shortly after finishing, detectives forwarded him a Polaroid of an unknown Florida teen on a bus that had come from Ramos.
But a former law enforcement source said agents found the teen in Ohio and that he was not Etan, the Post said.
The source said the photo was taken of a different teen on a bus where Ramos would lure boys.
Ramos, a convicted sex offender, remains in jail for separate crimes. Hernandez was arrested in May 2012 and remains in a detention center.
Other than his confession, there is no other evidence linking him to the disappearance, the newspaper said.
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