Documents / FOIA release
This Federal Bureau of Investigation file section collects 1949 and 1952 memoranda and public letters about flying saucers. Letters from citizens offering theories were acknowledged and forwarded to the Air Force, and Hoover passed along a report of objects over Thessalon Lake, Ontario, along with an anonymous German letter about a V-weapon disc. An Air Intelligence briefing said research had reached no satisfactory conclusion. Memos also trace how the negatives of a 1947 Phoenix disc photograph were handed to Air Force Intelligence.
“Office of Special Investigations”5 pages
Office Memorandum . UNITED STATES GOVERNMENT You inquired as to what was being done with reference to the information concerning flying saucers, which information was furnished by I desire to advise that a letter is being prepared for the Los Angeles Office suggesting that they make a discreet check of the background of the individual who wrote the letter to Winchell and thereafter interview him for details. It is believed that a letter is satisfactory inasmuch as it is noted that this alleged incident occurred in 1947.
FOIA release, from the fbi-vault collection. The PDF is mirrored here; the original link is under it. The text was read from the page images by an OCR model; expect the odd misread word. 67 pages are in the text index: search them above, or from the library's search.