A federal prosecutor In Nashville said Thursday that Hixson's Robin Smith was one of "three powerful politicians who used their influence to line their pockets."
Prosecutor Taylor Phillips said the other two were former Tennessee House Speaker Glen Casada and his former top aide Cade Cothren.
Casada and Cothren are standing trial on charges that include 20 federal counts of conspiracy, public corruption by fraud, bribery and name concealment, and money laundering.
Ms.
Smith earlier pleaded guilty to one count of honest services fraud and is due to be the star witness for the government.
She resigned her state legislative office when the scandal arose.
Prosecutor Phillips said the three found a way to "crack into a special pot of state money that was available only to legislators."
He said the plan included kickbacks, passed through companies and a fake company.
The prosecutor said it involved a fund that the 99 legislators could use for constituent mailings and surveys.
He said Cothren set up a company called Phoenix Solutions that was supposedly headed by Matthew Phoenix, who turned out to actually be Cothren himself.
The prosecutor said Casada and Ms. Smith received payments for other legislators who agreed to use Phoenix for their mailings.
Ed Yarbrough, representing Casada, said the investigation was brought on by current House Speaker Cameron Sexton, who he said is a political rival of Casada. He said when Sexton became speaker, he learned of the Phoenix situation and began working with the FBI. He said Speaker Sexton had an earlier relationship with the Memphis branch of the FBI on another matter.
Attorney Yarbrough said Casada had little involvement in the Phoenix situation, and only gained some $4,000-$7,000 out of it.
He told the jury that Speaker Sexton had it in for Casada since Casada supported Eric Swafford, who ran against Sexton for the legislature.
Joy Boyd Longnecker, representing Cothren, said he technically was not guilty of any of the federal charges and "the government is wasting your time."
She said similar mailer operations "have been going on for years. Its just politics and business as usual on the hill."
The attorney said Cothren "did a great job on the mailers and everybody got what they paid for."
She said Cothren "deeply regrets" what has been referred to during the trial as "the scandal." Cothren had resigned from his chief of staff position after publication of vulgar comments about women in emails.
The attorney said, "He has paid dearly for that."
Attorney Longnecker said the total amount spent in the mailer program was only about $51,000 and Cothren got around $8,000.
She said Cothren was highly sought by legislators as a "skilled political strategist." She said Cameron Sexton sought him out to help in his campaign for speaker even after Cothren had left the legislature.
The attorney said many legislators have additional jobs.