I used to work with a guy who was an extreme Type A personality. He owned a contracting company and he supported my project. He pushed himself to ridiculous limits until he had a heart attack. The doctors told him he needed to cut back on his activity. He relaxed for a few months and then came back with a vengeance. A year later, he had a second heart attack, this one much worse than the first. The doctor now referred to him as a ticking time bomb and said that he would die unexpectedly if he continued his pace. He has, and he’s still alive, though if he keeled over at any point I would be completely unsurprised. He’s only in his late 30’s.
If Breitbart had a history of heart problems, then this could very well be the case. I have a hard time believing the assassination angle as well because of the era we live in. Killing one man isn’t going to get rid of the evidence.
One need not get rid of the evidence, but merely intimidate those who might do anything with it. Take for example the gross criminality of Fast and Furious. The evidence against Holder is legion, and yet nobody in a position of authority is willing to do anything with it, not out of fear for their life (that we know of), but merely out of the fear of being branded a racist or losing their comfortable income and position.