Here is a memo dated March 6, 1967 regarding a walk-in lead.
You can see that Alcock doesn't quite believe the lead - "this man's appearance was very shabby and in some respects his story was not believable." Well, Limbough did claim that Tippit was Ruby's body-guard-boyfriend!
His story also made the newspapers. Here is a story by Washington Post reporter George Lardner from March 12, 1967.
Now, Limbough tells the press that "I think's a queer ring." Bill Gurvich, the Garrison investigator who defected in June 1967, said that "this sort of thing makes a mockery of our investigation ... this man is totally unreliable."
Mr. Limbough then went to the FBI because it did not appear that Garrison was interested in his story. Here is their five-page memo - and you can download it here if you want.
Well, I am not surprised that Garrison's staff never contacted Mr. Limbough again.
Well, guess who bought his story?
Joan Mellen, the author of A Farewell To Justice.
Here is a quote from page 112 of her book: "A Ruby employee named Clyde Limbough by then had revealed that he had seen Oswald in Ruby's office on three occasions, as the evidence that Oswald and Ruby were well acquainted accumulated.'
Her source is the Garrison memo above - but Mellen leaves out the reservations that James Alcock and William Gurvich had about Limbough. And, she says nothing about the fact that Limbough had been in mental institutions on two occasions (of course, perhaps she never saw the FBI memo)..