Investigators say 23-year-old Temar Bishop took the 20-year-old victim to the rooftop of a building in the Mitchell Houses in the Mott Haven section and attacked her.
The victim, a college student, was in Manhattan with friends and somehow ended up with the suspect in the Bronx just after 5 a.m. Saturday.
Police said Bishop punched, kicked and stomped on her head and body then raped her until she was unconscious.
The victim sustained a fractured nose and broken teeth and was taken to an area hospital for treatment.
Bishop was released on parole last July after serving a state prison sentence for robbery.
He is described as being 5-foot-9 and 150 pounds, last seen wearing a black shirt with the words "Super Dry Sport" in gold lettering, light colored shorts and white sneakers.
He is known to frequent areas in the Bronx and Brooklyn.
A $2,500 reward is being offered for information that leads to an arrest.
Anyone with information is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782).
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