Kirk had his own security on top of other security arranged because of his divisive and abrasively intolerant nature.
Have heard the shot came from the top of a building some distance away. Guessing
it would be a good shooter, even possibly an expert who took the shot.
And understand Kirk had far-right enemies, as well as people on the left.
It was Plato who said, “He, O men, is the wisest, who like Socrates, knows that his wisdom is in truth worth nothing”