A BlackRock ad that went viral the day after the assassination attempt on Donald Trump has been pulled because of the presence of a student in the background of the 30-second spot: Thomas Crooks, the 20-year-old who authorities say fired at the former president on Saturday. A rep for the investment behemoth explained that “in 2022, we ran an ad featuring a teacher from Bethel Park High School, in which several unpaid students briefly appeared in the background, including Thomas Matthew Crooks.” Reuters reports Crooks graduated from Bethel Park High in 2022. “We will make all video footage avai…