Story highlights Schock was indicted for allegedly defrauding the government last November

The Republican from Illinois resigned his seat in March 2015 amid a spending scandal

(CNN) A former Illinois congressman charged in a federal spending scandal claims a staffer in his office secretly recorded him, stole thousands of emails and pilfered travel receipts -- all to help the FBI build its criminal case last year, according to court filings on Tuesday.

Former Republican Rep. Aaron Schock was indicted on fraud charges last November after an investigation revealed that he allegedly used taxpayer money to fund lavish trips and events.

Schock alleges in Tuesday's court filings that the day after he announced his resignation from Congress in March 2015, government agents made a beeline to his office in Peoria, Illinois, and enlisted a "fairly junior staffer," who worked as an office manager, to act as a confidential informant for the FBI against the congressman.

"(T)he government met with their new CI almost daily to provide instructions, receive documents or other items the (informant) seized, discuss 'scenarios,' equip him with the recording device, and debrief him after completion of a monitoring and recording session," according to a court filing.

Not only did the informant allegedly wear a hidden device to record conversations with Schock and other staff members, but Schock's attorneys claim that federal agents directed the informant to "insert himself" in conversations that were protected by the attorney-client privilege, as the particular staff members involved were represented by counsel at the time, and the informant "purport(ed) to be represented by the same attorney as counsel for other staff members."

Read More