Secret Service is always on the roofs of buildings near a president's
outdoor event. I remember this from my attending a Reagan event in the
80s. Not securing these roofs had to be a deliberate act. Logically,
they suspected someone would try to kill Trump, just like in the
Kennedy and MLK assassinations.
 And dead assassins can't talk, just like Oswald. This whole thing
smells/ reeks of lies, just like the Kennedy assassination.