They give details of a warning to Robert Kennedy about an explosive book which mentioned his alleged affair with the actress.
The book claimed he was behind the Hollywood star’s murder.
The 11-page FBI document contains multiple memos – including one from J Edgar Hoover to Robert – written during a two-week period in 1964, regarding Frank Capell’s book The Strange Death of Marilyn Monroe.
The book claimed Robert Kennedy, who was then attorney general, had an affair with Marilyn and he was at her home when she committed suicide.
On July 8, 1964, Hoover wrote to Robert stating that Capell had said he would “make reference to your alleged friendship with Marilyn Monroe” and that he intended to “indicate in his book that you and Miss Monroe were intimate and that you were in Miss Monroe’s apartment at the time of her death.”
Marilyn died in 1962 of a barbiturate overdose.
Another FBI memo indicates the claim that Kennedy was with her was proven false, as Kennedy was in San Francisco at the time of her death.