Chuck Giancana, much like the testimony/evidence from mob lawyer Frank Ragano, is nearly impossible to substantiate, which makes it difficult from an academic standpoint to validate these sources. Obviously, you have to take them at face value, or discard them entirely. I do however think that there is some truth to what they say - mostly because after some time and research I still think the mob had some part in the assassination - but that you have to remember where the stuff is coming from, and put it into perspective.