I think the gunman has more in common with people who beat their wives than Bernie Sanders. Okay the 66 year old did not beat his wife (that we know of), but he has a history of domestic violence, and using a gun in instances that have a police report. This has been the case for 10 years with multiple incidents.
http://www.thedailybeast.com/congressional-shooter-loved-bernie-sanders-hated-racist-and-sexist-republicans
You see me talking about how the man beats his wife is called a leading comment. For example if this was not a comment but a question and instead of being RAFO if it was a court building, it would not be permissible for a lawyer to ask a defendant on the witness stand, so when did you stop beating your wife? It is the definition of a leading statement that poisons the thought process of the jury. Trying to connect this guy to Bernie Sanders is much the same thing.
-----
After all we have a violence problem in the United States. Too much gun deaths, too much domestic violence against family members, neighbors, strangers, etc. It only makes the news though and is not a statistic when it occurs to someone famous. Then we try to find blame, well the blame is this is an unhinged official and we have years of similar crimes occurring in the past, and the only difference is someone may have died in this most recent incident. 5 people are injured, the and the House Majority Whip (#3 in the Republican House Order) is still in critical condition.