I've been hearing names bandied about for decades without any evidence that they actually had any skill with a rifle. As Ruby showed, any slug-with police assistance-can jam a gun in somebody's gut and pull the trigger, but do you really want to be bet on some one who's never hit an animated targets that is moving in a vehicle?
As I tried to get the feds to understand that I trained for 5 1/2 years that the guy with the AK 47 and suicide vest is hardly going to be some one who included in the long term planning of ISIS.
Professional hit men? Met a few Mafia members with such responsibilities and one South African. Unlike the fictional writers frantic delusional scribbling about muscular dudes from Delta or one of the Seal Teams that have beautiful woman following them around, this guy looked like an elementary school teacher, but he was the real deal. Rhodesian SAS, Selous Scouts, and African Reconnaissance Commando and no I'm not going to mention his name or anybody else.
As I said I'm not collecting dues or charging admission and having satisfied my own curiosity I'm content to read others opinions. A bud in 22 SAS commented that who the men were actually pulled the triggers, they're back home raising a crop and playing with their kids and grandkids.
Steely eyed killers? Don't make me laugh! We had one guy in my dept that had been involved in 24 fatal shootings and you would have passed him by without a second glance.
The point is that there were no Mafia members at the autopsy or on the Warren Comission and besides having the EXPERIENCE AND SKILLS, the ability to lead a long and normal life without ever telling anyone is critical too.