The House select committee investigating the January 6, 2021, US Capitol insurrection is holding a hearing Tuesday focusing on the role of extremist groups in the deadly riot. In the leadup to the hearing, members of the committee said the presentation will zero in on connections between then-President Donald Trump’s administration and groups such as the Oath Keepers and Proud Boys. Here are some of the key figures that could come up in the committee’s hearing: Joe Biggs Joe Biggs, a Proud Boys leader from Florida and former InfoWars correspondent, assumed a top leadership role within the Proud Boys after the January 4 arrest of Proud Boys Chairman Enrique Tarrio, according to the Justice Department. Biggs allegedly led the Proud Boys in a march to and around the Capitol building, and was present at the initial breach of Capitol grounds. Biggs faces nine federal charges including seditious conspiracy and has pleaded not guilty. Michael Flynn Michael Flynn is a retired US Army lieutenant general and served as national security adviser for the first 23 days of the Trump administration. After reports that he had misled the administration over his communications with Russia before Trump took office, Flynn was forced to resign. He was charged with, pleaded guilty to – and then attempted to withdraw that plea – lying to the FBI over his Russian contacts. Flynn eventually received a presidential pardon from Trump ending the three-year legal saga. After the 2020 election, Flynn was heavily involved in the Stop the Steal movement. His outlandish theories about overturning the election eventually reached the White House, most notably during the December 2020 Oval Office meeting where Flynn and lawyer Sidney Powell suggested that the then-President should implement martial law or seize voting machines. Kelly Meggs Kelly Meggs is a leader of the Florida chapter of the Oath Keepers and is one of several members charged with seditious conspiracy. He has pleaded not guilty. Text messages from around January 6 show that Meggs discussed the possibility of using the Proud Boys as a “force multiplier” on January 6 with other Oath Keepers, and that he was in touch with former Trump adviser Roger Stone about providing security during the Stop the Steal rally. Meggs allegedly led the infamous first “stack” of Oath Keepers up the steps and into the Capitol building on January 6, according to the Justice Department. Once inside, Meggs allegedly went searching for House Speaker Nancy Pelosi. Ethan Nordean Ethan Nordean, a Proud Boys leader from Washington state, also assumed a top leadership role in the absence of Tarrio. Nordean, along with Biggs, led a large group of Proud Boys in a march from the Washington monument to the Capitol. Nordean faces nine federal charges including seditious conspiracy and has pleaded not guilty. Dominic Pezzola Rochester Proud Boys member Dominic Pezzola is accused of smashing a window with a stolen police officer’s riot shield, precipitating the first breach of the Capitol building. He was allegedly one of the first rioters inside, and was at the front of the group who chased Capitol Police Officer Eugene Goodman up the stairs. Pezzola faces 10 federal charges including seditious conspiracy and has pleaded not guilty. Sidney Powell Sidney Powell is an attorney and former prosecutor who became a legal hero in Trump-world for her defense of Flynn when he faced charges in Robert Mueller’s probe and later for her failed efforts to challenge the 2020 elections results. After the 2020 election, she joined Rudy Giuliani and other Trump attorneys in lobbing some of the most outlandish false election-rigging claims, as she famously promised that she was “going to release the Kraken” in her legal gambits. She now faces legal ethics complaints for how she handled the Trump-aligned post-election litigation. Before the 2020 election, she had represented Flynn, Trump’s former national security adviser, when he sought to back out of a plea deal he had reached with Mueller for false statements made to the FBI. Stewart Rhodes Stewart Rhodes, an Army veteran and graduate of Yale law school, founded the Oath Keepers in 2009 and has led the far-right organization ever since. Rhodes was at the Capitol on January 6 but is not alleged to have entered the building, though phone records show he allegedly communicated with members who did go inside the Capitol and with members staged at an armed “quick reaction force” just outside Washington, DC. Rhodes was also a member of a “VIP” Signal chat alongside Roger Stone, Ali Alexander, Alex Jones and other key Trump allies, according to people familiar with Signal messages that prosecutors have obtained. Rhodes, along with nine other members of the Oath Keepers, is set to go to trial in September on charges of seditious conspiracy. He is currently being held in a federal detention facility near Washington, DC. Rhodes has pleaded not guilty to all criminal charges stemming from January 6. Kellye SoRelle In 2020, Kellye SoRelle volunteered for Lawyers for Trump and assisted in some of the Trump campaign’s efforts to challenge the outcome of the presidential election. She is a close ally of Rhodes, and was photographed with him outside the Capitol on January 6. She has provided information to both the House select committee and the FBI but has not been charged with a crime. Roger Stone Longtime political operative and ally of Trump, Roger Stone was a large presence in the lead up to January 6, with connections to both Trump and far-right extremists involved in the Capitol riot. Stone, whom Trump pardoned in July 2020 after being convicted of crimes that included lying to Congress, attended a rally on January 5 and had a protective detail made up of members of the Oath Keepers, some of whom have been criminally charged with seditious conspiracy. On January 6, Stone was at Washington’s Willard hotel, where Trump supporters had set up a “war room.” According to former White House aide Cassidy Hutchinson’s testimony to the committee last month, Trump – the night before the Capitol riot – told chief of staff Mark Meadows to ask Stone and Flynn what was going to happen on January 6. Stone has testified before the committee, asserting his Fifth Amendment rights to every question. Enrique Tarrio Proud Boys Chairman Enrique Tarrio was arrested on unrelated offenses two days prior to January 6 and was not in Washington on the day of the attack, but is alleged to have stayed in touch with a rally planning group within the Proud Boys called the Ministry of Self Defense, or MOSD. The MOSD’s first event, according to prosecutors, was the January 6 Trump rally in Washington, and Tarrio sent the group a voice message on January 4 acknowledging they wanted to “storm the Capitol.” As the attack unfolded, Tarrio allegedly wrote in an encrypted message, “Make no mistake … We did this.” Tarrio, Biggs, Pezzola and Nordean are among the Proud Boys leaders charged with seditious conspiracy. Like the other three, Tarrio has pleaded not guilty. CORRECTION: This story has been updated to reflect that Trump ally Roger Stone was at the Willard hotel on January 6, 2021.