 The bandage, the result of the attempted assassination on Saturday, which we now know was carried out by Thomas Crooks, who was spotted on that building roof in Pennsylvania long before he took his first shots. ABC's Pierre Thomas has a timeline. Police see he is a range finder, which can be used to establish distance for target practice. And at 5.52 p.m., a sniper spotted Crooks on the roof roughly 20 minutes before he takes his first shot.