That's what this new book claims. Decide for yourself:
http://www.dailymail.co.uk/news/article-2630449/EXCLUSIVE-Bobby-Kennedy-ordered-Marilyn-Monroes-murder-lethal-injection-prevent-revealing-torrid-affairs-RFK-JFK-dirty-Kennedy-family-secrets-new-book-claims.html
http://www.dailymail.co.uk/news/article-2630449/EXCLUSIVE-Bobby-Kennedy-ordered-Marilyn-Monroes-murder-lethal-injection-prevent-revealing-torrid-affairs-RFK-JFK-dirty-Kennedy-family-secrets-new-book-claims.html