 And of all the rooftops, this is the one that most needed to be secured, but it wasn't. Apparently, there was just one police officer who responded in a meaningful way during this whole process before the shooting started. According to Associated Press, a local police officer heard all these people yelling about someone on the roof. Reportedly, the officer climbed up on the roof, at which point the gunman pointed his rifle at him. The officer dropped back down, retreated.