For years, the files have intrigued investigators, biographers and those who don't believe Monroe's death at her Los Angeles area home was a suicide.
A 1982 investigation by the Los Angeles District Attorney's Office found no evidence of foul play after reviewing all available investigative records, but noted that the FBI files were "heavily censored."
That characterization intrigued the man who performed Monroe's autopsy, Dr. Thomas Noguchi. While the DA investigation concluded he conducted a thorough autopsy, Noguchi has conceded that no one will likely ever know all the details of Monroe's death. The FBI files and confidential interviews conducted with the actress' friends that have never been made public might help, he wrote in his 1983 memoir "Coroner."
"On the basis of my own involvement in the case, beginning with the autopsy, I would call Monroe's suicide 'very probable,'" Noguchi wrote. "But I also believe that until the complete FBI files are made public and the notes and interviews of the suicide panel released, controversy will continue to swirl around her death."
Monroe's file begins in 1955 and mostly focuses on her travels and associations, searching for signs of leftist views and possible ties to communism. One entry, which previously had been almost completely redacted, concerned intelligence that Monroe and other entertainers sought visas to visit Russia that year.
The file continues up until the months before her death, and also includes several news stories and references to Norman Mailer's biography of the actress, which focused on questions about whether Monroe was killed by the government.
For all the focus on Monroe's closeness to suspected communists, the bureau never found any proof she was a member of the party.
"Subject's views are very positively and concisely leftist; however, if she is being actively used by the Communist Party, it is not general knowledge among those working with the movement in Los Angeles," a July 1962 entry in Monroe's file states.
Anthony McCartney can be reached at http://twitter.com/mccartneyAP