 The building that the shooter eventually climbed on top of. They were supposedly looking for threats in the crowd at the rally. But there were no officers or snipers on the roof for reasons that remain unexplained. Even though that would be the rational spot to place those snipers on top of the building rather than inside of it. But it's now an uncontested fact that the shooter used the police staging area as a vantage point to shoot Donald Trump.