WASHINGTON — In a surprise development, lawyers for former Rep. Aaron Schock, R-Ill., alleged on Tuesday that federal probers improperly turned a “fairly junior staffer” in Schock’s Peoria office into a “confidential informant” who secretly recorded him and stole documents.

Schock is fighting corruption charges, and his defense lawyers in the Tuesday filings said they were laying the groundwork to ask a judge to dismiss his indictment on, among other grounds, prosecutorial misconduct.

Schock’s attorneys are asking a judge to grant a motion to allow them to discover more information about the circumstances surrounding the informant passing documents, covert recordings and other information to federal agents while Schock was still a member of Congress, noting no “smoking gun” was found.

A federal grand jury in Springfield indicted Schock in November 2016 for allegedly using campaign and government funds improperly for cars, mileage reimbursements, interior decorating, a charter plane flight to a Bears game and sports tickets he resold for profit.

The 24-count indictment also accuses Schock, once a rising political star, of filing false income tax returns and covering up his alleged fraud schemes with fake invoices and false statements.

Schock resigned from Congress on March 17, 2015, under a cloud. The U.S. Attorney in Springfield launched its probe in mid-March of 2015. The man who would become the confidential informant — called the CI in the filings — was the first witness.

“The government has stated that it intends to use the recordings at trial, and, although it now states it will not use certain of the purloined material at any trial in the case, it has remained silent about whether it intends to use other documents it illegally obtained,” Schock’s McGuireWoods law firm attorneys George J. Terwilliger III; Robert J. Bittman; Benjamin L. Hatch, and Nicholas B. Lewis argued in their motion.

“In spite of these efforts, there is no indication that the government’s use of the CI produced the ‘smoking gun’ it no doubt sought by using him. The government, however, cannot run away from what was produced: a trail of improper — if not outright illegal — acts by the CI that remain not fully known to the defense in this case.

“Among what is unknown to Mr. Schock, and what the government has refused to disclose, is the full extent to which the prosecutor and the investigating agents directed the CI to engage in illegal and/or improper activities, and what use the government made of the ill-gotten fruits of the CI’s efforts,” they wrote.

The Schock lawyers assert “for at least the next several months, the CI while acting under the direction and control of the government” covertly:

• Secretly recorded conversations of Schock and Schock staffers who had hired lawyers to represent them. Those alleged actions, infringed “on the Attorney-Client and Speech or Debate Privilege,” Schock’s lawyers said.

• “Attempted — at the government’s direction — to steal privileged work product documents” related to Schock’s discussions with his defense team.

Schock and federal prosecutors in Springfield have been sparring for months over whether Schock needs to produce certain documents. Schock’s lawyers said the informant was able to obtain the work product of Schock’s first team of attorneys at Jones Day “long sought” by prosecutors.

• “Stole travel-related receipts in the District Office from the desk drawer of a staffer and provided those receipts to the government.”

• Stole “thousands” of emails from the official House account of a staffer.

For more than a year, Schock has been dividing his time between Los Angeles, where he is relatively unknown, and Peoria, where he became famous as one of the fastest-rising GOP political stars in Illinois. Schock has been working for a real estate development firm.