(CNN) Top leaders in the Oath Keepers, the far-right extremist group, have been turning over phones and digital files and sitting for interviews with the FBI -- and detailing how they worked to benefit Donald Trump's campaign and communicated with others in the former President's orbit, according to court records and multiple sources familiar with the federal investigation.
Kellye SoRelle, a lawyer working with the Oath Keepers, told CNN that she has met with the FBI several times and handed over phones.
She declined to say more about what she's shared with investigators, but her ties to the group have come up in court filings, including a virtual meeting a week after the 2020 presidential election when Oath Keepers talk about heading to Washington, DC, and SoRelle briefs them about the campaign's legal fight.
"I've done interviews. I've done everything. I'm helping them," SoRelle said about her cooperation with investigators. She does not represent any Oath Keepers in their criminal proceedings and has not been charged in the seditious conspiracy case against several members in connection with the January 6, 2021, insurrection.
Investigators also have learned about encrypted messages on the app Signal leading up to January 6, in which the Oath Keepers were messaging high-profile, right-wing political organizers, according to four people familiar with its existence. The Justice Department recently provided records of the chat to defense attorneys in the sedition case, some of the people said.
In court last week, prosecutors also disclosed how the Oath Keepers' leader Stewart Rhodes called an unnamed person on speakerphone from a hotel suite on the evening of January 6, asking to speak directly to Trump and urging the person to tell Trump to call upon groups like the Oath Keepers to "forcefully oppose the transfer of power."
Prosecutors have said they expect to bring more charges against people affiliated with extremist groups. Grand jury activity continues apace. And investigators are talking to a wide range of people, including organizers of pro-Trump rallies that preceded the US Capitol attack, while seeking information about attempts to impede the certification of President Joe Biden's electoral win.
All are signs that the biggest investigation in Justice Department history is expanding beyond the hundreds of alleged rioters and exploring connections with more politically connected players.
"I think it's self-evident that they are continuing to work their way up the food chain to get to who their grand prize is," Lee Bright, a defense lawyer for Rhodes, said in an interview, referring to speculation that the Justice Department will eventually target Trump.
Rhodes himself met with the FBI multiple times before his arrest in January and handed over his electronics, his lawyers say. Rhodes has pleaded not guilty and is set to go to trial in July.
Several Trump supporters and operatives also have indicated they are sharing information with prosecutors.
"Stop the Steal" organizer Ali Alexander, who received a grand jury subpoena for information about the pro-Trump rally on January 6, said he would be willing to cooperate and has been responsive to prosecutors' requests, according to a person familiar with his situation.
Alex Jones, the far-right media figure and conspiracy theorist who spoke at a January 5 pro-Trump rally, has been approached by federal investigators for a meeting, though he hasn't done one yet, according to his attorney.
The attorney, Federico Andino Reynal, told CNN that Jones is demanding protection from prosecution if he is to talk because he is "suspicious of the government's motives for seeking an interview given the highly partisan nature of the investigation," and says he is innocent of any crime.
Jones also was involved in pro-Trump rallies in Washington in November and December in 2020 and received protection from right-wing volunteers while in town. Groups like the Oath Keepers provided security to him, Roger Stone and other prominent pro-Trump rally speakers.
According to the people familiar with the Signal messages that prosecutors have accessed, Jones appeared alongside Roger Stone, a staunch Trump ally and confidant, as well as Alexander and members of the Oath Keepers for what was called a "VIP" chat.
This chat is only one of dozens of Signal threads, with more than 100,000 texts total, related to January 6 from Rhodes' phone, which has become "key to proving or disproving a conspiracy" case against him, according to recent court filings. It's not clear if the VIP Signal chat ever expanded beyond discussion of security around the rallies.
Lawyers for Alexander and Jones didn't respond to questions about the chats. On a social media account last week, Stone posted it was false that he texted with Rhodes, and that "discussion of logistics for a speech at a legally permitted event Jan. 5 proves nothing." None of the three rally speakers are facing charges.
Robert Caron, another person who says he helped to investigate election fraud allegations, told CNN he was approached by two FBI agents at a hotel in Toronto in December, then sat down to speak with them about key people connected to efforts to overturn the election. Caron says the agents indicated they were working on the investigation into violence on January 6 and the lead-up to the insurrection.
Caron provided the business card of one of the FBI agents, who referred questions to the bureau's public information office.
Officials from the FBI and DC US Attorney's Office have declined to comment on the ongoing investigation.
Caron would not say who tapped him to investigate election fraud claims. Caron says he told the FBI that he had cautioned prominent right-wing figures after the election that he hadn't found evidence of voting machines flipping votes.
Prosecutors have cited some of the information about the Oath Keepers in court filings as evidence that defendants charged in the conspiracy case engaged in ongoing discussions about how to oppose the lawful transfer of presidential power.
In the case of William Todd Wilson, a leader of the North Carolina chapter of the Oath Keepers who pleaded guilty to seditious conspiracy and agreed to cooperate with investigators last week, prosecutors said in a court filing that he huddled with Rhodes and others in a private suite at a Washington hotel after leaving the Capitol grounds on January 6 and overheard Rhodes on the phone with someone trying to get in touch with Trump.
"This individual denied Rhodes' request to speak directly with President Trump," the filing states, without naming the person or indicating if investigators looked into the story further.
Prosecutors also have obtained from an informant a transcript of a GoToMeeting virtual event on November 9, 2020, during which SoRelle, a lawyer from Texas, provided an update to Oath Keepers on legal challenges on behalf of Trump, according to court proceedings. Rhodes also spoke at the meeting.
In the transcript, SoRelle described various "pods" of people working on the "project to try to solve the mystery of the ballots." She said there was the Republican National Committee pod, the "Back-Channel pod" of QAnon followers, and the Campaign pod that included the "Giuliani pals," an apparent reference to associates of Trump lawyer Rudy Giuliani.
"So I've been in communication," SoRelle is quoted as saying at the virtual event. "I obviously work the RNC version of it, and then I'm in -- I like the Q crowd, they're kind of fun, and then I've been meeting with the Campaign crowd."
In an interview with CNN, SoRelle disputes that she is the speaker but says she did work with the Trump campaign, describing various "teams" searching for voter fraud. She also said she went to Michigan -- a swing state where Joe Biden narrowly won -- after the election to collect affidavits about supposed fraud to send to the Trump campaign, with some support from the Republican Party, and that the Oath Keepers protected her in that mission.
A spokesperson for the Republican National Committee said it has no connection to the Oath Keepers or any DOJ investigation into them, and spokespeople for Trump didn't respond to questions from CNN in recent days.
Federal grand juries have met every day since mid-April in the downtown Washington courthouse, approving indictments related to January 6 nearly every day. Prosecutors assigned to these cases and law enforcement witnesses frequently pop in and out of the confidential proceedings.
As of last week, prosecutors have signed up more than 10 defendants as cooperators against Oath Keepers and the Proud Boys, whose leaders are charged with separate conspiracy allegations. The case against the Oath Keepers has taken several steps forward in recent days, with two new cooperators against Rhodes and others announced in the past week.
Behind the scenes, defense attorneys continue to receive new information that federal investigators are collecting as part of the discovery process -- a sign the conspiracy investigations related to far-right groups aren't over.
Prosecutors, in feeling out potential conspiracy defendants' willingness to plead guilty, have asked if some would admit there was a plan to "stop the steal" of the election, an apparent reference to the slogan used by pro-Trump rally organizers, one person familiar with talks told CNN.
Attorney General Merrick Garland has publicly professed the investigation would proceed methodically. In most criminal investigations, that often means prosecutors pursue less significant figures to plead guilty and potentially cooperate as they gradually build evidence for higher-profile cases. Garland specifically noted in January that the federal evidence-collection efforts would dig into both physical and digital evidence and money.
"The facts tell us where to go next," the attorney general said.
As the grand juries working through January 6-related cases stay active, some political figures have sought out criminal defense lawyers, in case the DOJ shows interest in them in the future, according to people familiar with the reach-outs.
"There is criminal exposure for any number of people who were part of the organization and planning that were not storming the Capitol," Doug Jones, the former Democratic senator and US Attorney in Alabama who is now an attorney in private practice in DC and has been closely following the January 6 investigation. "From the very beginning, the Justice Department has been casting a wide net."
But, he added: "It's difficult to assess where they are."
Jones pointed out that believing false election fraud claims is not a crime. Yet there could still be legal jeopardy for those who understood there was no widespread fraud and still wanted to obstruct Congress by spreading false information to Trump supporters.
"You can espouse these crazy theories, but you've got to connect the dots to somebody trying to put something into action," Jones said.
No advisers working with Trump on the election result have been charged with a crime.
At the Justice Department, officials have deliberated internally how to navigate the thorny issues these cases present, including ensuring prosecutors are not targeting Constitutionally protected political speech, according to sources familiar with the matter.
This could become particularly difficult as investigators examine the activities of people associated with political fundraising and events that preceded the violence.
Federal investigators also have sought to bolster the conspiracy cases by drawing connections to violence that occurred at other rallies in the weeks before January 6, according to the sources and court filings. DOJ officials believe that could help prosecutors show there was a pattern of violence, and that the Capitol riot wasn't just a spontaneous event, sources say.
In December 2020, weeks before the January 6 attack, some of the same extremist groups that participated in the Capitol riot were part of violent clashes with police and counter protesters in Washington during a weekend of rallies to protest the election results. Police said dozens were arrested and four churches vandalized. A November 2020 protest also broke out in violence.