Federal agents reportedly raided former Rep. Aaron Schock's campaign office in Illinois Thursday, amid an ongoing investigation into his official expenses. 

According to local reports, the FBI showed up at the Republican's Junction City office with a search warrant. The Peoria Journal Star reported that at least 14 agents spent hours loading up boxes and other items into two trucks. 

The search comes as a federal grand jury hears testimony from current and former Schock staffers. 

Schock resigned from Congress in March following months of media reports about lavish office and political spending, including improper mileage reimbursements, trips on donors' aircraft and office decorations in the style of the TV show "Downton Abbey." 

The Justice Department has issued subpoenas to current and former Schock staffers as it examines his expense accounts, campaign spending and relationships with donors. 

The Associated Press contributed to this report.