A classified file released by the FBI shows how the agency tracked Marilyn Monroe’s suspected ties to communism in 1956.

The agency documented an anonymous phone call to the New York Daily News that year warning that playwright Arthur Miller was a communist and Marilyn Monroe had “drifted into the communist orbit” after her marriage to him earlier that year.

The file is just one piece of the puzzle about what the FBI knew about Marilyn Monroe when she died in August 1962.

The Associated Press waging an ongoing campaign to have more of the FBI documents released by the agency, coinciding with the 50th anniversary Marilyn Monroe’s death.

The redacted document reveals that on July 11, 1956, the agency got a tip that an anonymous male caller phoned the Daily News to report that the actress’s company, Marilyn Monroe Productions, was “filled with communists” and that money from the company was being used to finance communist activities.

The caller said Arthur Miller’s marriage to Marilyn Monroe during a Jewish ceremony less than a months earlier was a “coverup”.

Marilyn Monroe and Arthur Miller were both suspected of communist activities by the FBI

Arthur Miller, the man said, “was still a member of the CP [communist party] and was their cultural front man”.

The FBI has long made portions of its documents about Monroe public, but most of them are heavily redacted.

However, the FBI claims it has lost its files on the actress and cannot release them.

Finding out precisely when the records were moved – as the FBI says has happened – required the filing of yet another, still-pending Freedom of Information Act request.

The most recent version of the files is publicly available on the bureau’s website, The Vault, which periodically posts FBI records on celebrities, government officials, spies and criminals.

The AP appealed the FBI’s continued censorship of its Marilyn Monroe files, noting the agency has not given “any legal or factual analysis of the foreseeable harm that might result from the release of the full records”.

Marilyn Monroe’s star power and fears she might be recruited by the Communist Party during the tenure of longtime FBI Director J. Edgar Hoover led to reports being taken on her activities and relationships, including her marriage to playwright Arthur Miller.

Marilyn 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. 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 Marilyn Monroe was killed by the government.

There have been two major government investigations into Marilyn Monroe’s demise – the original inquiry immediately after her death and another effort by the Los Angeles District Attorney’s Office in 1982. The second inquiry, released in December 1982, reviewed all files available investigative reports, including files compiled by the FBI on her death. The records, the DA’s office noted, were “heavily censored”.

That mention intrigued the man who performed Marilyn Monroe’s autopsy, Dr. Thomas Noguchi. While the DA investigation concluded he conducted a thorough autopsy, Thomas Noguchi has conceded that no one will likely ever know all the details of Marilyn 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>>,” Thomas 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.”