No, there's only one individual they created the atmosphere that led to it, and all others like it, that did not occur prior to 2017. Unless you want to include Squeaky Fromme from half a century ago.
ONE PERSON MAY HAVE SHOT AND KILLED CHARLIE KIRK BUT THERE ARE MANY OTHERS WHO ARE RESPONSIBLE FOR THE MURDER. AND ALL OF THEM DESERVE TO BE BROUGHT TO JUSTICE FOR INCITING VIOLENCE.