The Associated Press has accessed, via a request under the Freedom of Information Act, the FBI investigation file of the $600 million grossing porn film Deep Throat. The file shows how far the FBI was willing to go to prevent open sexuality on screen.

The file, amassing 4,800 pages, still leaves out 1,000 pages exempt under the FOIA. Having reviewed only 498 pages, the AP has learned that top FBI agents from Honolulu and Detroit took part, though the film was shot in Miami. Even Mark Felt, the alter ego of the film’s namesake and Watergate informant, is attributed in some of the pages though the extent of his involvement is unclear.

The pages describe seizing of copies, interviews with the actors (including Linda Lovelace) and reel messengers, analyzing negatives in a lab, and more. They call director Gerard Damiano “somewhat cooperative.” The only reference to any crime is the interstate transportation of obscene material, mentioned throughout.

The movie, made for $25,000, was the highest grossing movie of its time and is arguably the most famous American porn of all time.