The agency will examine the matter after being demanded to do so by lawmakers, who accused the lack of security for "the overrun of government offices by terrorists."
"Our work will primarily focus on the extent of coordination between federal and local entities for security and emergency support," said Orice Brown, managing director of GAO's Office of Congressional Relations.
Charles Johnson Jr., the managing director of the agency's Homeland Security and Justice team, will be leading the investigation and will start the work soon, Brown said.
GAO will not examine the specific actions of individual members of Congress to prevent overlap with other government investigations.
The Jan. 6 protest ended in the deaths of five people, including a U.S. Capitol Police officer, after a rally held by former President Donald Trump that intended to demonstrate against the congressional approval of President Biden's triumph in the 2020 election.
The events ended in Trump's second impeachment, led by the Democratic-controlled House. A trial in the Senate is pending, though Trump left office on Wednesday. The former president was impeached on a charge of "incitement of insurrection."
Alan M. Hantman, an American architect who served as the 10th Architect of the Capitol from February 1997 until February 2007 wrote online explaining his opinion about the matter, stating, “Security measures we designed weren't meant for a mob.”
“Televised images of chanting, screaming mobs attacking government buildings beamed from countries torn by war are nothing new to worldwide audiences. Impossibly, these images now include the dome recognized around the world, the one with a statue of Freedom crowning its majestic form. The one in our nation’s capital.”
“As the 10th architect of the Capitol, I had the great honor to serve from 1997 to 2007 as head of the 2,200-member legislative branch agency dedicated to preserving, maintaining, upgrading and expanding this magnificent structure, the patrimony of the American people. I came to know and love every corner of it and the democracy it represents.”
“On 9/11, the heroism of Flight 93’s passengers and crew averted that imminent threat to the Capitol. We followed up by strengthening agency communication, coordination and mutual assistance agreements among multiple federal and state security organizations.”
“But through all our security planning sessions with multiple federal security agencies, through all our congressional hearings before House and Senate committees, no one ever raised the specter of a mass insurrection advancing on the Capitol. The possibility of a domestic terrorism mob attack never arose.”