Students at the City University of New York's Graduate School of
Journalism received the FBI documents after filing a Freedom of Information
Act request. The university posted the documents on its Web site Thursday.
The FBI declined to comment on why it tracked the writer. Halberstam's widow, Jean, didn't immediately return a telephone message Friday.
Halberstam won a Pulitzer for his coverage of the Vietnam War while working as a reporter for The New York Times. He later wrote a book critical of U.S. involvement in Southeast Asia.
Halberstam was killed in an April 2007 car crash in Menlo Park, Calif., near San Francisco. He was 73.