 One rally goer told CBS News, I was just standing there like everyone else, just waiting for Trump. And as Trump started, I noticed two officers looking for somebody. So I was looking around myself and seen a guy, like your English, seen a guy on top of one of the buildings go in between one building to the next and went and told the officer he was up there. Another witness who spoke to BBC News said the gunman was bear crawling up the roof of the unsecured building. He was pointing at the gunman for two to three minutes and tried to alert police to the threat.