How did Marilyn Monroe die? The Unheard Tapes theories explained

The new film uses audio recordings from research that investigative journalist Anthony Summers began in 1982, when the Los Angeles County District Attorney reopened the investigation into Monroe’s death.

Summer’s own investigation resulted in 650 tape-recorded interviews and eventually led to a 1985 Monroe biography, Goddess: The Secret Lives of Marilyn Monroe, which presented new evidence about the circumstances surrounding Monroe’s death.

Delving into Marilyn's fraught childhood, which was spent in and out of foster homes, and depicting a dark and sleazy Hollywood which exploited its female talent, the film also details her high-profile marriages and alleged relationships with Bobby and John F Kennedy.

According to Summers' interviews with federal operatives, intelligence agencies were also apparently concerned that Monroe had forged associations with communist expatriates connected to Cuba's Fidel Castro to whom she might be divulging government secrets.

The documentary also features recordings of Marilyn throughout too, in which her love for cinema from a young age became clear, as she says Jean Harlow was her inspiration.

Contributing voices include that of her psychiatrist Ralph Greenson and his family, actress Jane Russell, filmmaker John Huston and director Billy Wilder.

But how did Marilyn Monroe die, exactly? Well, here are the theories surrounding Monroe's death that the film explores...

Marilyn Monroe died by overdose

In August 1962, an official coroner ruled Marilyn Monroe's untimely death at 36 as an overdose and possible suicide. Monroe was found unresponsive in her bed next to a bottle of sleeping pills and a telephone off the hook beside her at her 12305 Fifth Helena Drive home in Los Angeles.

After the case was reopened in 1982, the original finding remained unchanged, with a district attorney stating that Monroe either took her own life or died accidentally. The case was closed.

Journalist Summers believes that Monroe either died by suicide or from an accidental overdose but suggests that it's possible FBI investigators cleared her home to remove anything that would indicate Monroe's alleged involvement with Bobby and John F Kennedy.

Possible Kennedy brothers connection?

There are inconsistencies with the time, location and who exactly was at the scene of Monroe's death.

According to surveillance expert Reed Wilson, Bobby Kennedy called Monroe on the night of her death, who claimed that the actress told him to leave her alone.

Marilyn Monroe's housekeeper Eunice Murray claimed to have found Monroe's body around 3am, but the widow of Monroe's publicist Arthur Jacobs Natalie Jacobs says her husband was called with the news she had died around 11pm.

The documentary also alleges that an FBI investigator arrived at her home shortly after her death to clear her house and remove anything that could compromise the Kennedy brothers.

Other inconsistencies around time are detailed, with senior FBI agent Jim Doyle telling Summers that the federal officials arrived long before police came to her home at the reported time of 4:25am.

"There were some [Bureau] people there that normally wouldn’t have been there," Doyle says. "They came on the scene immediately. Before anybody even realised what happened. It had to be instructions from someone high up, higher than [former FBI director J Edgar Hoover]. The [attorney] general or the president."

Even stranger are claims from paramedics called to the scene that Monroe was comatose but still alive when they found her, and that they transported her by ambulance to an emergency room in Santa Monica.

"No, she wasn't [dead at home]," says ambulance company owner Walter Schaefer.

One of Schaefer's former drivers, Ken Hunter, had been called to Monroe's home on the night of her death, with Schaefer claiming that Monroe was alive when he arrived.

Journalist and writer John Sherlock also said that Monroe's psychiatrist Greenson told him that she died en route to the hospital, and was returned back to her home.

"She died in the ambulance," Sherlock alleges in the documentary. "Then they took her back to the house. [Greenson] told me he was in the ambulance."

Law enforcement informant Harry Hall suggests that Monroe's death became a "hush hush" matter.

"The man that was really involved was the boss [Bobby]. He was the attorney general of the United States, so he'd have the FBI do anything," Hall claims.

"People that knew, knew that they didn't want Bobby Kennedy’s name brought into this, because his brother was the president. They had done everything to hush this up."

Marilyn Monroe was murdered?

Despite all the murky circumstances surrounding her death, journalist Summers believes Monroe died of suicide or an accidental overdose.

"I did not find out anything that convinced me that she had been deliberately killed," he concludes.

There's still so much that is not known about Monroe's last moments, with a haunting audio recording of Monroe ending the documentary: "The true things rarely get into circulation. It's usually the false things."

The Mystery of Marilyn Monroe: The Unheard Tapes is streaming now on Netflix.

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