NASHVILLE (AP) — A Tennessee Republican lawmaker resigned Monday shortly after court documents were unsealed revealing that she faces a federal wire fraud charge involving a disgraced former state House speaker.

The legal team for Rep. Robin Smith also has reached a plea deal with prosecutors, court documents show. A plea hearing for the lawmaker from Hixson is scheduled for Tuesday.

The charging document alleges that Smith worked closely with former House Speaker Glen Casada and his then-chief of staff, Cade Cothren, through a political consulting firm that they used to funnel money to themselves while concealing their involvement in it. Casada and Cothren are described but not named in the document.

Smith "devised and intended to devise a scheme and artifice to defraud and deprive the citizens of the Middle District of Tennessee and the government of Tennessee of their right to the honest services of a public official," prosecutors said.

Casada resigned from the top leadership post in August 2019 after revelations he exchanged sexually explicit text messages about women with Cothren years ago. In January 2021, FBI agents searched the homes and offices of several state lawmakers, including those of Casada and Smith. Cothren's home was also searched. At the time, federal investigators declined to give a reason for the searches. To date, no charges against Cothren or Casada have been announced.

However, the revelation of Monday's documents appears to give more insight of the raid. The documents state Cothren launched a political consulting firm called Phoenix Solutions, LLC that was designed 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 "Matthew Phoenix" when in fact it was Cothren using a made-up alias, the documents allege.

Authorities say Phoenix Solutions was initially set up to provide mail and consulting political services for lawmakers facing primary election opponents. Its work later extended into sending taxpayer-funded mailings to constituents, from which Phoenix Solutions, a separate company owned by Smith, and another company owned by Casada received almost $52,000 combined in 2020, the documents state.

Smith, Cothren and Casada hid Cothren's involvement in Phoenix Solutions "due to the expectation that Phoenix Solutions would not be approved by the Tennessee House Speaker's Office, acting on behalf of the state, or hired as a vendor by individual members if (Cothren's) involvement was disclosed." They also hid that Cothren "kicked back" portions of the profits to Smith and Casada, allegedly because lawmakers would not use Phoenix Solutions as a vendor if they knew of Cothren's involvement, prosecutors allege.

Cothren and Casada did not immediately respond to text messages from the AP seeking their comment Monday. An attorney for Smith likewise did not immediately respond to a request for comment.

In 2020, Cothren's then-girlfriend and Cothren exchanged emails as "Candice" and "Matthew" to make it appear as though Phoenix Solutions employees needed to secure an outstanding payment that the state had not yet paid, authorities said. That exchange was forwarded to Smith.

According to prosecutors, Smith told multiple Republican lawmakers in 2020 that "Matthew Phoenix and his associate, Candice, got tired of living in the Washington, D.C. area and decided to move back home to New Mexico, where Phoenix started Phoenix Solutions."

At one point, the documents allege Smith emailed Cothren saying that he "may have to assume the role of Matthew again." He replied saying, "Matthew, reporting for duty!" and included a GIF of "a salute from Harrison Ford's character Han Solo in the movie Star Wars," officials said.

Casada had previously announced he wouldn't run for reelection last year, and would instead run for Williamson County clerk.

House Speaker Cameron Sexton said in an emailed statement that Monday was a "sad day," adding that he "will continue to cooperate fully with federal authorities as the investigation continues."

"More than a year ago, federal authorities started an investigation into public corruption. Today's news and the ultimate resignation of Rep. Smith is a sad day for all who know her," said Sexton, who took over the top position when Casada resigned in 2019.

Yet Sexton added it was "clear in the charging documents that certain individuals used their official capacity to target General Assembly members and the Republican Caucus by using a fake company to siphon off money illegally and deceptively."

Smith, 58, was elected to the House of Representatives in 2018. She had previously served as chair of the Tennessee Republican Party and a policy advisor to Republican U.S. Rep. Mark Green.

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.

Regulators decided to reopen the probe into the Faith Family Freedom Fund after the PAC's treasurer testified in January that she is Cothren's former girlfriend and opened the PAC because Cothren asked her to, saying Cothren assured her she was doing nothing wrong and that she took no further action, according to the Chattanooga Times Free Press.

The PAC attacked then-Rep. Rick Tillis, the brother of North Carolina U.S. Sen. Thom Tillis. He lost his 2020 GOP primary election to Rep. Todd Warner, who was one of the lawmakers subject to the FBI searches.