Former President Donald Trump was the target of an assassination attempt at a Pennsylvania rally Saturday that set off panic as a bloodied Trump was surrounded by Secret Service and hurried into his vehicle. A former fire chief attending the rally with family was killed, as was the gunman. Two other people were critically wounded. The Associated Press obtained video showing the shooter on a rooftop moments before the attack. Signs of trouble were evident in the minutes before shots rang out at Donald Trump’s rally in Pennsylvania: Police had a report of a suspicious man pacing near the magnetometers and were apparently exchanging photos of the suspect. Witnesses pointed and shouted at an armed man on a nearby roof. When a police officer climbed up to the roof to investigate, the gunman turned and pointed his rifle at him. But the officer did not — or could not — fire a single shot. A sniper cut down 20-year-old Thomas Matthew Crooks within seconds of him firing an AR-style rifle toward the former president, but it was too late. Now investigators are trying to painstakingly piece together how an armed man with no military background managed to reach high ground and get the jump on teams of Secret Service agents.