Updated: February 23, 2021 17:09 IST Much remains unknown about what happened before and during the assault, and lawmakers are expected to aggressively question the former officials about what went wrong Share Article AAA Trump supporters try to break through a police barrier at the Capitol in Washington on January 6, 2021. | Photo Credit: AP Much remains unknown about what happened before and during the assault, and lawmakers are expected to aggressively question the former officials about what went wrong Congress is set to hear from former U.S. Capitol security officials for the first time about the massive law enforcement failures on January 6, the day a violent mob laid siege to the building and interrupted the presidential electoral count.