A campaign finance watchdog group has requested that the justice department open a criminal investigation into the figures behind a series of deceptive Facebook ads that promoted Green party candidates in the 2018 midterm elections.

A Guardian investigation recently revealed that the ads were placed by a major conservative marketing firm, contradicting an inquiry by the Federal Election Commission (FEC), which accepted the statement of Evan Muhlstein that he was responsible for the ads and had failed to comply with FEC reporting requirements due to “inexperience”.

The ads were placed by a Facebook Page called America Progress Now (APN) in the days ahead of the 2018 election. APN was not registered with the FEC at the time, in violation of federal laws requiring disclosures of so-called independent expenditures.

The Campaign Legal Center, the non-partisan watchdog group requesting the investigation, filed a complaint with the FEC about the group in 2019, but the FEC declined to investigate after Muhlstein came forward to take responsibility for the ads.

“Muhlstein gave the FEC the impression that he alone had created the APN page, placed the ads, and financed the ads, and that the reason that APN did not comply with legal disclosure was that he was unsophisticated,” said Brendan Fischer, the director of federal reform at the Campaign Legal Center.

Internal Facebook documents reviewed by the Guardian revealed that APN was in fact controlled by three conservative political operatives, including Jake Hoffman, the chief executive of Rally Forge, a political marketing firm with close ties to the pro-Trump youth group Turning Point USA. Rally Forge had significant experience running independent expenditures in federal races, and would have been aware of reporting requirements. Hoffman is currently a member of the Arizona state legislature.

“Muhlstein concealed all of those material facts, and that concealment is what led the FEC to dismiss the complaint,” Fischer said. “The DoJ should investigate whether Muhlstein violated the law by making material misrepresentations to the FEC … This looks like a very strong case.”

While the FEC has the power to enforce civil violations of campaign finance laws, “knowing and willful” violations are criminal, and therefore handled by the justice department, Fischer said.

Ann Ravel, a former FEC commissioner, previously told the Guardian that Muhlstein’s statements to the FEC looked like a “clear fraud” and should be referred to the justice department for investigation.

The Campaign Legal Center is also requesting a criminal investigation into whether APN knowingly and willfully violated campaign finance laws.

“It appears that the entire purpose of this scheme was evading the disclosure laws designed to inform voters,” Fischer said. “These are potentially serious violations.”

He added: “It has to be worth noting that this does not reflect well on the FEC. The willingness of the agency to accept these claims at face value does not inspire confidence in the agency that is exclusively charged with enforcing campaign finance law.”

Muhlstein did not respond to repeated queries by the Guardian ahead of publication of the investigation. Hoffman said in a statement, “Rally Forge is a marketing agency, not a compliance company. Furthermore, it is my understanding that the small handful of ads, totaling less than 2,500 dollars, which qualified as independent expenditures, have been fully disclosed by the responsible organization in coordination with the FEC.”