The reason that people continue to suggest Mob involvement in the JFK killing is that they are willing to accept a standard of proof that would be unacceptably low in any other situation.

"so and so knew someone" proves that so and so knew someone,and nothing more."This one told that one and it was confirmed by the other one",is not evidence.

How is it possible that a guy spills the beans on the crime of the century to a Newsday reporter,yet he is not arrested as an accessory,not questioned by any law enforcement agency,and in fact,is not even taken seriously?
The possibility that the guy is full of more sh*t than a Christmas turkey comes to mind.

Time after time,what we get is second and third party recollections made by people with an agenda,whether it be to plug their book,or to promote their TV appearance circuit,or just to get some attention.

Ruby was sent to silence Oswald? Then who was going to silence Ruby? Early on,Ruby made "mysterious" allusions to a plot. What is not publicized are the statements that Ruby made before he died,years later,in which he admits that he was acting on his own and just wanted to kill the guy who killed his idol,JFK. If he had any kind of real info,he could have testified,gotten protection, and spent the rest of his life in relative comfort instead of dying alone in a cell,(actually a hospital)ravaged by cancer.
Or if you believe that "The Mob" could have still gotten to Ruby,why would they let him live for years after killing LHO,thereby exposing themselves to the risk of him snitching at any time.
If Ruby had anything to reveal,he could have executed a detailed statement containing real facts and evidence to his lawyer,or a trusted friend, to be made public after his death.

Was there a possibility that the Mob killed JFK? Yes,provided that the only standard of acceptable proof is rumor,innuendo,and speculation.Once you bring EVIDENCE of any kind, whether it be physical,direct eyewitness testimony,incriminating documents,etc.into the equation,The possibility falls to near zero.