Joseph Pabon, 27, was found guilty of the kidnap and murder of Eridania Rodriguez in July 2009.
Mrs Rodriguez, 46, disappeared while working a night shift cleaning at a skyscraper in Manhattan's downtown financial district. Her body was found after an extensive four-day search.
Pabon, 27, has denied killing the married mother-of-three. His lawyers said authorities had woven a criminal case out of coincidences and innocent conduct.
However jurors concluded he abducted the woman as she worked and smothered her, covering her mouth with industrial tape.
He faces up to life in prison when he is sentenced on May 11. Mrs Rodriguez's sister, Denise Figueroa, wept as she left the New York courthouse. Read More