An eyewitness who was outside the site of Donald Trump’s campaign speech in Pennsylvania claims he saw the gunman climb onto a roof and tried to alert police.

“We noticed someone crawling, walking on all fours, on the roof of the building next to us, about 15 meters away from us,” the witness told BBC News.

“We were standing there pointing at this man crawling on the roof… We could see him clearly, as well as the gun he had,” he said. He added that they notified the police and that the officers “didn’t know what was going on”.

“I’m thinking, ‘Why is Trump still talking? Why hasn’t he been taken away? I’m standing there pointing at him with my hand, for two, three minutes. The Secret Service is looking at us. I’m pointing at the ceiling and all of a sudden there’s five gunshots,'” he added.

The testimony raises serious questions

Commenting on the testimony, a CNN analyst said it raised “serious questions.”

“There will be a thorough examination of who knew what, how it was communicated and who decided to take or not take action,” he said.