FBI agents and the House panel investigating the January 6 attack on the Capitol have both learned of an alleged plan by allies of retired army Lt Gen Michael Flynn to gather “intelligence” on top Republicans to “move” them to back election audits in key states Trump lost, said ex-whistleblower Everett Stern who talked to the panel and the FBI.

Stern, who runs the intelligence firm Tactical Rabbit and is a Republican vying for a Senate seat in Pennsylvania, in multiple interviews with the Guardian said two Flynn associates with the rightwing Patriot Caucus group enlisted his help in April in a scheme to seek potentially damaging information on two Republican members of Congress to prod them to back an audit of the 2020 vote that Joe Biden won.

Stern told the Guardian he spent several hours in November telling House panel investigators about the alleged drive by Flynn associates who sought campaign finance and other dirt on Pennsylvania’s senator Pat Toomey and congressman Brian Fitzpatrick to win their support for an audit to bolster Trump’s debunked charges that Biden’s win was fraudulent.

A long shot candidate to succeed the retiring Toomey, Stern said he alerted the FBI in June when he learned more details of the bizarre drive by Flynn allies to specifically target the two Republicans, both of whom backed impeaching Trump after the January 6 insurrection.

The efforts by Flynn’s Patriot Caucus allies were launched after Trump failed to block Biden from taking office, and are part of a wider drive by Trump loyalists and Flynn to help boost Trump’s political fortunes via more state audits nationwide into false charges that Biden’s win was rigged, and elect like-minded candidates in key states to top electoral offices.

Stern provided text messages, emails and other documents revealing he had multiple contacts with one of the Patriot Caucus members, Velma Anne Ruth, and two other influential Flynn allies, Houston real estate mogul Al Hartman and former army green beret Ivan Raiklin, who were pushing audits in several key states.

Stern said Flynn’s Patriot Caucus associates first approached him in Pennsylvania for possible help after an April Republican party event, and soon after told Stern in phone calls they worked with Flynn and the Patriot Caucus, and planned to recruit “former domestic and foreign intelligence officials” to facilitate their scheme.

The plan by Flynn’s allies alarmed Stern, but as a former whistleblower involved in exposing a large bank money laundering scandal by HSBC in 2012, he told the Guardian he decided to play along for a few months to glean information to expose the Trump allies’ scheme.

Stern expressed dismay that Flynn’s Patriot Caucus associates “don’t understand that Biden is the president. They wanted to collect information through Tactical Rabbit and my campaign,” to turn up the heat on Toomey and Fitzpatrick to back an audit which Stern viewed as potentially “extortion”.

Stern gave the Guardian a voice mail he received in which Hartman talked about leaning on moderate Republican “RINOs” in Pennsylvania to gain support for an audit of that state’s vote which Biden won by over 80,000, and Hartman said a similar drive in Michigan was needed.

Stern said Hartman wanted to use Tactical Rabbit’s intelligence gathering tools and his campaign to dig up potentially embarrassing campaign finance information and other dirt about the Pennsylvania members, plus Republican political figures in Michigan who were also resisting audits.

Hartman and Raiklin also talked with Stern about meeting Flynn, Trump’s disgraced ex-national security adviser, and proposed compensating him for his information via campaign donations, said Stern.

In an April exchange of Hartman text messages seen by the Guardian, Hartman asked a Flynn scheduler to help “connect” Flynn with Stern whose Senate campaign and credentials he touted highly, calling Stern a “strong believer”, in their cause.

Although Stern tipped off the FBI in June about what he deemed a threat to national security and he said he met with agents again in November, it’s not clear if his allegations are still being pursued.

Stern’s allegations have echoes of Flynn’s scheming with Trump and other loyalists in late 2020 to thwart Biden’s win, efforts that included a White House meeting with Trump where Flynn proposed declaring martial law in several states Biden won and then rerunning the election there.

In November, the House panel probing the January 6 Capitol attack subpoenaed Flynn who Trump had pardoned post election even though he had pled guilty twice to lying to the FBI during the Russia investigation. In response to the subpoena to testify and turn over documents, Flynn sued the panel but a judge quickly dismissed his lawsuit last month.

John Sipher, who was in the CIA’s clandestine services for 28 years, shares Stern’s view of Flynn who he knew in the military and shortly thereafter. “I am appalled by what he has become,” Sipher said in an email.

Asked if he thought the FBI was pursuing Stern’s charges, Sipher said: “I would hope and assume they are taking this seriously.”

While Fitzpatrick and Toomey were the main “targets” Stern said other Pennsylvania officials including judges were also being targeted by the Flynn allies as they sought to ramp up pressure for an audit in the state.

Neither Fitzpatrick or Toomey’s offices replied to multiple requests for comment.

The Patriot Caucus, a coalition of Patriot and other rightwing groups in some two dozen states with which Raiklin and Hartman have ties, according to Stern and documents, has worked with Trump loyalists like Flynn to push audits in key states Biden won, and backed Trump allies for governor, and other top posts in states like Pennsylvania and Arizona Trump lost.

Flynn himself on 7 January publicly endorsed another Trump ally and election audit promoter, Doug Mastriano for governor in Pennsylvania, at a campaign rally also attended by Raiklin.

Flynn has also endorsed two Trump backed candidates in Arizona: Kari Lake, an ex-Fox News figure for governor, and Mark Finchem, a state representative who attended the January 6 Stop the Steal rally, for secretary of state.

To coordinate national efforts, Raiklin and Hartman on 3 July spearheaded one of a series of “Election Integrity” calls with Trump loyalists, lawyers and donors to discuss the status of audits efforts in several states and other plans to cast doubt on Biden’s win, according to an Arizona senate document shared by the watchdog group American Oversight.

“Join us every second Saturday for SITUATION UPDATES and COLLABORATION from active leaders in the election remediation process at state level – attorneys with Mike Lindell and Patrick Byrne, data analysts, state legislators, gubernatorial candidates, and grassroots activists whose goal is completing a cyber forensic audit in their state,” the Arizona document reads.

A who’s who list of Trump loyalists and groups invited to join these calls included the America Project and America’s Future, both of which Flynn played key roles with as they poured some $2m into a discredited audit of Arizona’s largest county, plus the Patriot Caucus’ Velma Anne Ruth, Finchem and Byrne, the millionaire chief financier of the Arizona audit.

Hartman in emails with Stern obtained by the Guardian invited him in June to attend a religious far right meeting known as Ziklag in Dallas where he could meet separately with Flynn. Stern said Hartman told him a “private meeting was going to be arranged with Flynn” who Stern was told wanted to meet him.

After indicating to Hartman he would attend, Stern opted to cancel at the last minute after his lawyer indicated there could be legal repercussions from a meeting with Flynn. “I thought it was extremely dangerous to meet with a three star general who I believed had broken the law.”

“They planned to give my campaign funds to help me” develop damaging information on Toomey and Fitzpatrick, Stern claimed. “It was like a wink, wink. Hartman is the man behind the curtain. He’s an operative and financier,” promoting audits.

Hartman has long been a donor to the right. He’s on the advisory council for the pro Trump Turning Point USA and has been active in the conservative donor network led by oil billionaire Charles Koch.

Raiklin, an army reserve officer who reportedly has known Flynn since 2014, is facing an internal army reserve probe into possible violations of rules barring partisan political activity, according to a military official who spoke to Reuters last month.

Raiklin in December 2020 outlined a wild scheme in tweets and a podcast to thwart Biden’s win, charging a vast conspiracy that included Pence, intelligence, China and Big Tech, as Reuters reported. Raiklin told Trump to “activate the emergency broadcast system,” and deployed the hashtag #FightLikeAFlynn, stressing that “we the people are going to force this plan on them”.

Neither Hartman or Raiklin replied to multiple calls seeking comment.

A Flynn scheduler did not respond to questions for the story.

Velma Anne Ruth with the Patriot Caucus, who was photographed with Stern at a June event in Pennsylvania where she wore a tank top that said General Flynn, called Stern’s charges “delusional, fabricated and defamatory”, in a text message. Stern said he shared the photo and other documents involving exchanges he had with Ruth with the FBI.

Senior ex-prosecutors and intelligence officials say Stern’s allegations merit law enforcement attention.

“Stern’s allegations suggest serious crimes,” said ex-prosecutor Paul Rosenzweig who worked on Ken Starr’s team during the impeachment of Bill Clinton. “If his allegations were corroborated by extrinsic evidence they clearly would warrant investigation.”

Former CIA official Sipher, who has spoken with Stern before, said: “Everett is someone with a strong sense of right and wrong, and willing to suffer the consequences of doing the right thing. We would be better served to have more people like Everett in public life.”