We will start this off with a UPI story from June 11, 1968, just six days after the assassination of Robert Kennedy, quoting Mark Lane:
Sylvia Meagher wrote a letter to Kerry Thornley, and wondered if Jim Garrison would back up the Mark Lane story.
Thornley wrote Meagher back, and was anxious to write about Mark Lane.
Of course, it didn't take long for Garrison to repeat the Mark Lane story!
Here is the article that Kerry Thornley wrote.
Update
Clyde Tolson, #2 at FBI, says what he really thinks of Robert Kennedy
William Sullivan, the #4 man at the FBI, describes a high level FBI meeting in spring, 1968. "Hoover was not present, and Clyde Tolson [FBI #2 and Hoover's boyfriend] was presiding in his absence. I was one of eight men who heard Tolson respond to the mention of [RFK's] name by saying, 'I hope someone shoots and kills the son of a bitch.' This was five or six weeks before the California primary." [William Sullivan, The Bureau: My Thirty Years in the FBI]