He was in the sniper den for about 12 hours, how did he know to be there?
Mesia maggots leaked Trumps schedule
12 hours exposure is 10 hours more than necessary, with more exposure to be found out by some passerby or checked out by a local police officer.
It is unlikely he would have been there so long if he had known when and where Trump would be.
If he had done his homework from open sources, which it appears he had, there was a pretty good reason to guess he would have an opportunity at that location.
He was stalking Trump for nearly a month.
With the vulnerabilities the administration made possible, it is not surprising he found one vulnerability in a month.
It may be there were other close calls. We may never know.
He had a time machine. Same one he used to go back and write a confession and give it to his friend to hold on to.