NASHVILLE (AP) — Tennessee House Republican lawmakers say they were betrayed by one of their own after they hired a shadowy political consulting firm talked up by a colleague who has since pleaded guilty to fraud in an alleged kickback scheme that also implicates a former House speaker and others.

House Republican Caucus Chairman Jeremy Faison told reporters that GOP caucus members had no reason to suspect fraud when they hired Phoenix Solutions to perform campaign and related services for lawmakers. Faison promised "greater scrutiny every time" on hiring vendors, saying they will always be established companies.

Faison's comments were in response to the guilty plea on a wire fraud charge by former Republican state Rep. Robin Smith of Hixson, entered Tuesday in Nashville federal court. Authorities say she, former House Speaker Glen Casada and his one-time chief of staff, Cade Cothren, created Phoenix Solutions as a way to illegally funnel money to themselves through both campaign and taxpayer-funded work. Smith resigned her seat Monday.

Phoenix Solutions, another separate company owned by Smith, and a company owned by Casada received almost $52,000 combined in 2020 through the taxpayer-funded mailer program, not accounting for the campaign materials for other lawmakers, the court documents state. So far, prosecutors have not announced any charges against Casada or Cothren. Neither man was referred to by name in the charging documents but it was clear based on descriptions provided who they were.

The documents state Cothren launched Phoenix Solutions, LLC to offer mail and consulting services to lawmakers in 2019 with Smith's and Casada's "knowledge and support." All three claimed the firm was run by a certain "Matthew Phoenix," whose signature even ended up on an IRS document, when in fact it was Cothren using an alias, the documents allege.

Republican House Majority Leader William Lamberth applauded the FBI for "ferreting out that lie" and holding Smith responsible. But he said it doesn't change the fact that he's "livid" about the situation.

"It breaks my heart man, but yeah it makes me really angry that one of our members would lie and bring the caucus into something that was their fault," Lamberth told reporters. "They didn't have to make up a company."

Casada resigned from the top leadership post in 2019 after revelations he exchanged sexually explicit text messages about women years ago with Cothren. Not long before that, Cothren also left his post over the texts, coupled with an admission he used cocaine inside a legislative office building when he held a previous job. Casada kept his legislative seat, but has previously announced he won't seek reelection so he can run for Williamson County clerk.

Smith touted Phoenix Solutions to fellow House Republicans on multiple occasions, saying it was her preferred survey mailer company and was run by Matthew Phoenix and his associate Candice, who both got tired of living in Washington and moved to New Mexico, prosecutors allege. The role of Candice, sometimes appearing in fabricated email exchanges, was played by Cothren's then-girlfriend, who was not named in the documents, according to prosecutors.

The three hid Cothren's involvement in Phoenix Solutions, and concealed that Cothren "kicked back" portions of profits to Casada and Smith, because they feared the House speaker's office and individual lawmakers would not approve the company's use if the information got out, prosecutors claim.

Faison, who has served as caucus chairman since 2019, said that he and other Republican lawmakers were convinced that the person on the other end of the line conducting business with them was "Matthew Phoenix."

"We as a caucus campaign finance committee reached out to Matthew Phoenix, spoke to the man, got W9s, everything was in order," Faison said.

Meanwhile, Casada's successor, House Speaker Cameron Sexton, told reporters Thursday that two legislative staffers who had been put on paid leave after a 2021 FBI raid would no longer be employees beginning Friday. Sexton has said he's fully cooperating with the investigation.

Casada has attended legislative meetings this week. Smith promised to cooperate with authorities in her plea deal, including as a potential witness. Cothren, meanwhile, has informed state campaign finance regulators that he is invoking his Fifth Amendment right against self-incrimination and won't abide by a subpoena in an investigation surrounding a political action committee.

Longtime Tennessee public interest lobbyist Dick Williams, who heads Common Cause Tennessee, said the alleged Phoenix Solutions scheme is a "more extreme" example that likely doesn't indicate a larger problem with the system, which can always use fine-tuning.

"It's an example that in any group of people, including legislators, you're going to have a few people that are wanting to game the system, one way or another, and be deceitful of, supposedly, their friends even," Williams said.