As lawyers for indicted Cook County Commissioner William Beavers argue their client is being punished because he wouldn’t be an informant for the feds, prosecutors are now acknowledging the government initially asked for Beavers’ cooperation relating to two unnamed public officials.

Since he was indicted for tax evasion in February, Beavers has claimed he’s being punished because he refused to be a “stool pigeon” for the feds against fellow Cook County Commissioner John Daley, the brother of Chicago’s former mayor.

Federal prosecutors didn’t name the public officials in court documents filed late Thursday afternoon, and Federal Judge James Zagel barred defense attorneys from bringing up the encounter in Beavers’ federal trial, which starts Monday.

But the filing adds a new element to what had been largely a sideshow in the case: Beavers’ claim that the government is squeezing him because he wouldn’t wear a wire.

“Now, four days prior to trial, the government admits for the first time that Beavers was asked to cooperate,” Beavers’ lawyers said in a court filing Wednesday.

His attorneys said they got a letter Wednesday from the government stating that when agents first confronted Beavers, they asked for his cooperation. Beavers’ attorneys claim that letter mentioned two names: ‘Daley’ and ‘Stroger,’ suggesting Commissioner Daley and former Cook County Board President Todd Stroger, who was a political ally of Beavers.

In court filings Thursday, prosecutors confirm they sent that letter to provide “additional details concerning the agents’ present memories” of the night they first told Beavers he was being investigated.

Prosecutors acknowledged that the agents asked for Beavers’ cooperation.

“Only one of the agents recalls any names being mentioned in connection with this request, and that agent recalls (1) the last names of two public officials were mentioned, and (2) as to one of those officials, the defendant commented that, if he had any information, he would have provided it a long time ago,” the government said in its Thursday court filings.

A spokesman for the U.S. Attorney’s office declined to identify the two public officials.

Stroger and Daley did not immediately return phone calls for comment, though Daley has previously denied he’s the target of any investigation. Neither man – nor any other public officials – has been accused of wrongdoing in connection with Beavers’ tax evasion case.

Beavers’ lawyers argue the commissioner’s prosecution is “vindictive,” and the case should be tossed out.

“Mr. Beavers told them he did not wanna cooperate. Maybe not in those words, but he told them that, and the next thing you know, he gets indicted,” defense attorney Aaron Goldstein said after a court hearing Thursday afternoon.

Federal prosecutors say that claim is “without merit,” and Zagel seemed to agree Thursday, suggesting Beavers’ refusal to cooperate with the government isn’t relevant to the tax evasion case.

Beavers, an outspoken pol who was a long-time alderman before being elected to the County Board in 2006, was indicted in February for allegedly paying himself more than $226,000 out of his campaign accounts, but not paying taxes on the money. Between 2006 and 2008, Beavers also allegedly used the $1,200 monthly stipend that’s given to Cook County commissioners for personal use, but didn’t report it on tax returns.

Both sides are set to meet in court again Friday morning to hash out other pretrial motions.  

The trial is expected to start Monday.