 Listen to this. This is pretty amazing. Thomas Crooks asked his boss for the day off, telling him he had something to do before traveling to Saturday's Trump rally. Agents found him in their sights, and one pulled the trigger seconds after the 20-year-old shot dead. Pennsylvania Fire Chief Corey Camparator critically injuring two others. They were looking at him while they was looking at him. It emerged on Tuesday the killer perpetrated the security area of the rally three hours before carrying out the attack.