MIAMI - When the FBI investigated the landmark 1972 porno movie "Deep Throat," the case touched the highest levels of the FBI, even its second-in-command W. Mark Felt, the shadowy Watergate informant whose "Deep Throat" alias was taken from the movie's title.

The FBI documents newly released to The Associated Press reveal the bureau's sprawling and ultimately vain attempt to stop the spread of a movie some saw as the victory of a cultural and sexual revolution and others saw as simply decadent.

Agents seized copies of the movie, had negatives analyzed in labs and interviewed everyone from actors and producers to messengers who delivered reels to theaters.

Officials at every level of government tried to stop screenings and obscenity trials continued for years. But in the end, experts say, it represents the end of an era in which the government sought to stop the changing cultural tides.