There is some innuendo going around--nobody is saying it outright but there are hints--on Fox et al--that there could be more than just another crazed nutjob. Some say the Trump campaign had asked for more security and were refused. A couple of people interviewed at the rally say they saw the guy on the roof and the rifle and told the Secret Service and were ignored. The implications of course are an inside job.
I am not going to speculate without more information--I resist being a conspiracy theorist especially when that would be entirely irresponsible--but I pick up on these things.
And I honestly think hope this kind of speculation is totally unfounded.