Most probably, she was involved with Robert Kennedy.
I think by this point, the whole world knows she was involved with him. As it turns out, an FBI field representative received a letter in 1964 where it was clearly written that Marilyn Monroe and then-attorney general Robert F. Kennedy were having an “affair” from late 1961 to 1962.
Robert Kennedy was emotionally involved with Marilyn Monroe, and he repeatedly promised her he would divorce his wife. The agent who took the letter to headquarters mentioned that he didn’t know the source and couldn’t properly evaluate the authenticity of this information.
But nowadays, it is generally accepted that at some point, Monroe was romantically involved with the Kennedy brothers, and it seems that a lot of people have testified to this.
In the latest Netflix documentary about the actress, Jeanne Martin, the wife of Dean Martin, who was a regular at Kennedy’s parties, confirmed that Monroe was, at some point, involved with both brothers.
For many years, rumors that the Kennedys orchestrated the cover-up that followed Monroe’s death investigation continued to surface. Up until this day, these are nothing but rumors because of a lack of documentation.
They successfully got rid of all the records, and if you go to any police department or even the district attorney’s office, there’s nothing there.