More than 170 cases opened in federal probe of U.S. Capitol attack

FBI official calls initial cases ‘just the tip of the iceberg’

Protesters enter the Senate Chamber on Jan. 6, 2021, in Washington, D.C. Congress held a joint session that day to ratify President-elect Joe Biden's 306-232 Electoral College win over President Donald Trump. Pro-Trump extremists entered the U.S. Capitol building after mass demonstrations in the nation's capital. (Win McNamee/Getty Images)