A man was arrested Thursday after he scaled a fence at the FBI Chicago office and began hurling rocks at the building, said Rob Sperling, a spokesman for the Federal Protective Service. The incident ended without injury around 11 a.m. but the man involved, who was not named by authorities, was taken to a hospital for evaluation. The bureau did not say what it believed the manâs motive was. FBI offices throughout the country have been on high-alert in the aftermath of a raid of former President Donald Trump's residence at Mar-A-Lago earlier this month. Since the raid, the agency has reported an increase in threats at its field offices, most notably in Cincinnatiâwhere a gunman failed to breach a field office before he led law enforcement on an hours-long chase that ended with him being killed in a corn field. The man killed, Ricky Shiffer, made social media posts leading up the attack that said he was preparing for a âcivil warâ and was ready to kill federal agents âon site,â all stemming from the Mar-A-Lago raid.