Many theories include whether Dr Ralph Greenson and/or Eunice Murray killed Marilyn either by accident or murder.
Although I am a big fan of Donald Spoto’s work, I don’t believe his theory on this. I used to though. Until reading up on some documents and interviews with coroners.
The main theory is that Greenson and Murray administered an enema. However, due to the faecal matter present at the autopsy, this is impossible. Discolourisation is common in death in general so this is not a factor. Marilyn DID have enemas for dietary and medical purposes in the past but not on this date.
So, did they kill her any other way?
Science, (as mentioned in previous answers) show that is highly unlikely that she was killed by any other means and that it is incredibly possible she died via oral overdose.
Why would they want to kill Marilyn (always a question you need to ask)? People say it’s because Marilyn was going to sack them. Now, why would you kill someone that was going to stop using your services? Surely that would end your services when they were dead.
Although Murray’s story kept changing and Greenson was a manipulator, it’s unlikely they would’ve killed her. as there is no evidence to support this.