Beavers is accused of not paying taxes on campaign funds diverted for personal use. His trial was scheduled to begin Monday but was delayed so attorneys could fine-tune the jury questionnaire.
Beavers told reporters Monday, not only is he not afraid of the feds, he isn't afraid to testify, if needed, at his tax-evasion trial.
"I'm gonna get on the stand, testify, I'm gonna tell the truth," Beavers said. "It's going to be up to the jury. It's not going to be up to me or anybody else. It's going to be up to the jury."
The 77-year-old Cook County commissioner is accused of failing to pay income taxes on a portion of campaign funds he took for personal expenses.
Beavers is also charged with not paying taxes on campaign contributions he placed in a city retirement fund in order to more than double his monthly pension.
Prosecutors say the alleged wrongdoing took place between 2006 and 2008.
"They tell some tall tales, and I've got to straighten them out," said Beavers.
Beavers said the charges are retribution for not agreeing to wear a wire on John Daley, a Cook County commissioner and brother of former Chicago Mayor Richard M. Daley.
"They asked me to be a stool pigeon. I'm not a stool pigeon, and that is what this is all about," Beavers said.
Beavers and his team of lawyers say the money taken from the campaign fund was paid back and tax returns were amended.
Prosecutors allege Beavers made those moves after he learned he was under investigation. The defense denies that.
"Once you hear what happened here and find out the time period when receipts are given, the time period when money is given back, and you go through it, you're going to see there's only one answer here as to why a prosecution came at all: and that answer is going to be because he wouldn't cooperate with the government," said Beavers' attorney Sam Adam Jr.
Jurors will fill that questionnaire Tuesday morning. If a jury is seated by Wednesday, opening statements will follow.
Anxious to tell his side of the story, William Beavers is not likely to take the witness stand until next week.
If he is convicted, Beavers faces up to three years in prison.