Police search Manhattan building for Etan Patz, child missing since 1979

Authorities in New York may finally be zeroing in on Etan Patz, the boy who disappeared 33 years ago and became the first missing child to be featured on a milk carton.

NYPD officers and FBI agents were searching a Manhattan basement Thursday, acting on new clues to the landmark case. Etan was last seen May 25, 1979 walking two blocks from his family's home in the SoHo section of Manhattan to a bus stop for the ride to school.

The 6-year-old boy was the subject of one of the most extensive missing-child searches ever. He was never found, but was officially declared dead in 2001.

NYPD spokesman Paul Browne told the Associated Press that the building being searched is roughly a block from where the family lived. Browne said the excavation stems from a recently ordered review of the case by Manhattan District Attorney Cy Vance, who re-opened the case after taking office in 2010.

Browne said a forensic team would dig up a floor and search through the rubble for blood, clothing or human remains. The work is expected to take as many as five days.

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    He wouldn't say what evidence led investigators to the property, but a law enforcement official, speaking on condition of anonymity, told The Associated Press that at the time of the boy's disappearance, the building housed the workspace of a carpenter who was thought to have been friendly with the boy.

    In the past few months, the official said, investigators had received information that Etan's remains might be buried in the basement. Then, within the past few weeks, an FBI dog indicated the possible presence of human remains in the space, prompting the decision to dig.

    "There's an active investigation on Prince Street," a police source told FoxNews.com. Additional details were not available.

    FBI officials are looking at possible suspects in the case, WABC/Channel 7 reports. Some sources told ABC News that prosecutors are now skeptical whether convicted child sex abuser Jose Antonio Ramos -- long considered Patz abductor and killer -- did in fact commit the crime.

    At least two suspects have been investigated in connection to the boy's disappearance, although they have not been identified, ABC News reports.

    The Associated Press contributed to this report.