WASHINGTON (AP) — Federal authorities and experts who study online extremism are warning of a risk of additional attacks on federal law enforcement following the FBI’s search of ex-President Donald Trump’s Florida home. Following the Mar-a-Lago search, online posts blaming the FBI soared, as did open references to civil war. A Pennsylvania man was arrested Monday after authorities say he posted violent threats against the FBI on Trump’s social media platform. Last week, a man armed with an AR-15 tried to breach FBI offices in Cincinnati and was killed after firing on police. Extremism experts warn the violence could escalate as investigations into Trump play out.