A key group of Republican attorneys general that donated $150,000 to co-sponsor the 6 January rally where Donald Trump pushed his false claims of election fraud before the Capitol attack could draw scrutiny from a House committee investigating the events on or in the lead-up to the riot.

The group – a part of the Republican Attorneys General Association (Raga) called the Rule of Law Defense Fund – has attracted strong criticism from watchdogs and ex-prosecutors even as Raga looks forward to next year’s midterm elections and many of its members are fighting on numerous fronts against Joe Biden’s agenda.

The controversy around Raga appears to be yet another way that Trump and his supporters have increased their grip on more mainstream elements of the Republican party, and involved them in efforts to further their agenda.

The RLDF, the policy arm of Raga, ponied up $150,000 for the 6 January rally, and arranged robocalls the day before informing people that “we will march to the Capitol and tell Congress to stop the steal,” a message that was probably reinforced by Texas’s attorney general, Ken Paxton, who told Trump’s rally: “We will not quit fighting.”

Watchdog criticism of the Raga policy arm that backed the rally stresses that the group’s funding and robocalls occurred after dozens of court rulings rejected Trump’s claims of fraud. They say it undermines respect for the nation’s laws, as well as departing from the group’s main focus of helping get Republican attorneys general elected.

Further, the rally funding and robocalls by the RLDF sparked resignations of high-level officials, including the Raga chairman, the Georgia attorney general, who broached concern about the group’s direction when he stepped down.

The controversies about Raga’s rally activities come as the group has received a hefty $5.5m from the dark money Concord Fund since the start of 2020, which can help Republican attorneys general in the 2022 elections, and as many Republican attorneys general including Paxton have filed lawsuits to thwart Biden’s energy, immigration and vaccine policies.

The $150,000 check that the RLDF donated to the rally came from the Publix supermarket heir Julie Jenkins Fancelli, funds that ProPublica reported were arranged by the Republican fundraiser Caroline Wren, a “VIP adviser” to the rally who has been subpoenaed by the House committee investigating the 6 January Capitol attack.

Asked about scrutiny of Raga and its big donation for the rally, a House select committee spokesperson told the Guardian that it “is seeking information about a number of events that took place in the lead-up to the 6 January attack, including details about who planned, coordinated, paid, or received funds related to those events”.

Some watchdog groups deplore Raga’s role in the rally. “It was clear before 6 January that the planned rally was based on lies, partisanship, and disrespect for the rule of law,” Austin Evers, the executive director of American Oversight said in a statement.

“That’s what Raga and its corporate sponsors chose to fund. The fact that the rally turned into a violent assault on democracy itself makes Raga’s involvement worse … Raga and its funders should be held accountable.”

Likewise, some ex-prosecutors express strong concerns about the message that the robocalls by Raga’s political arm conveyed.

“Attorneys general are supposed to support adherence to the law,” said Paul Pelletier, a former acting chief of the fraud section at the DoJ. “By the time of the rally every court in the country had affirmed the lawfulness of the election results and had specifically rejected charges of fraud. At that stage, it seems Raga, by urging protesters to ‘stop the steal’, was simply promoting an unlawful attack on our democracy – the antithesis of their mission.”

Raga’s then executive director, who resigned soon after the Capitol attack, denounced the violence by the mob, which resulted in several deaths and ore than 140 injured police officers, and in a sweeping denial stated that neither Raga nor the RLDF had any “involvement in the planning, sponsoring or the organization of the protest”.

But campaign finance watchdogs don’t buy Raga’s denial.

“Raga’s policy arm and other groups helped organize a rally that preceded a riot and an attack on democracy,” said Sheila Krumholz, the executive director of Open Secrets.

The fallout at Raga over its 6 January role increased in April when Chris Carr, the Georgia AG who chaired the overall group, announced suddenly he was stepping down as chair, and noted a “significant difference of opinion” about Raga’s direction in a resignation letter.

Later in April, Raga announced that Peter Bisbee, who had overseen the RLDF when the robocalls occurred, was being promoted to become Raga’s executive director.

Since Biden took office many Raga members, including Paxton and others from Missouri and Louisiana, have filed a wave of lawsuits to block several Biden priorities.

The surge of lawsuits is seen as potentially helpful in the runup to 2022 campaigns when 30 Republican and Democratic attorneys general will be running for re-election after serving four-year terms. In the 2020 elections, Raga for the first time targeted incumbent Democratic attorneys general with ads, and may try to oust Democratic attorneys general who were key Biden allies last year in states such as Pennsylvania and Michigan where Trump and his allies pushed false claims of fraud.

While Raga this year witnessed some corporate backers hold back checks after 6 January, its fundraising was bolstered when it pulled in $2.5m, by far its largest contribution and more than a third of the total raised for the first half of 2021, from the dark money Concord Fund, which the Federalist Society executive Leonard Leo helped create.

Raga also received $3m in 2020 from the Concord Fund.

Raga roped in low-six-figure checks in 2021 from oil and gas giants like Koch Industries and the Anschutz Corp and the Koch-backed Americans for Prosperity.

Over the years, Raga has garnered financial support from industries, including fossil fuels and pharmaceuticals, which GOP AGs have backed in major litigation.

Trump himself is slated to host a fundraiser next month at his Mar-a-Lago club for Paxton, which appears to underscore his gratitude and the tough re-election campaign the former Raga chairman is facing as three Republican challengers to him have emerged. Those opponents are focusing on Paxton’s legal problems: he was indicted on securities fraud six years ago and the FBI reportedly has been investigating allegations of bribery and other misconduct.

Last fall, some of Paxton’s former deputies accused him of improperly helping an Austin real estate developer and donor, prompting more FBI scrutiny.

Paxton, who has not been charged, has broadly denied any wrongdoing. Paxton’s office this August released an unsigned 374-page report rebutting the charges of former aides and claiming he was exonerated, but attorneys for the ex-employees responded the report was “full of half truths, outright lies and glaring omissions”.