The FBI's dossier on Chávez was obtained under the Freedom of Information Act (FOIA), which contains provisions that allowed the FBI to withhold portions of the documents from public view. Indeed, many parts—and in some cases, entire pages—have been excised from the files. Nevertheless, the collection provides a compelling window into the efforts of the farmworker movement, as well as the values and methods of the FBI itself.
The bulk of these documents from the summer and fall of 1968 deal with an FBI investigation of a suspicious letter sent to César Chávez that contained death threats against the labor leader. The first 11 pages of the file show copies of the letter and envelope as well as latent fingerprints developed from each, although all of these are illegible.
In a report dated August 13, 1968, the FBI's field office in San Francisco stated that the Delano postmaster furnished a theatening letter—first postmarked in San Jose and then Gilroy, from where it was forwarded to Delano—addressed to Chávez with a return address bearing the name Tirso P. Mellosa. The FBI provided a translation of the letter from Spanish, which in part reads, "See how you like grenades or mortars because the machine gun makes too much noise and you may pass on to your better life...Scared."
On August 16, the San Francisco office sent a memo with the following leads: it would interview UFWOC officials in Gilroy for clues on the identity of Mellosa, and Sacramento would collect the fingerprints of the Delano postmaster and Tony Ordain, the office manager of the United Farm Workers Organizing Committee (UFWOC), as well as other individuals who may have handled the letter.
In a report dated September 30, the FBI stated that UFWOC staffers in Gilroy were not familiar with the name Tirso P. Mellosa, nor could they provide the names of individuals who could be considered suspects in the matter. On October 2, the Sacramento office reported that a palm print on the letter belonged to David Michael Fishlow, the editor of the UFWOC's El Malcriado newspaper. The other fingerprints were not identical to those of Fishlow, the Delano postmaster, Ordain, or others who had reportedly handled the letter.
In a related case, the U.S. Department of Justice's Criminal Division informed the FBI on October 3 that Chávez and Dolores Huerta had received threatening phone calls.