Other details:
Shooters phone pinged at location on 7/7. Indicating advance planning.
Slope of roof did impede line of sight of snipers. Kill shot was insanely difficult. 9 inch window through tree from 400 yards.
Shooter never approached magnetometer with the range finder.
There's a working THEORY among investigators that shooter initially intended a mass casualty event focused on rally crowd. Once shooter recognized police were onto him he scaled roof to avoid police and Trump opportunity presented itself.