Four congressional staffers have told the U.S. House that they've been subpoenaed by the federal court in Springfield, Illinois, where a grand jury is conducting a probe into the spending of former U.S. Rep. Aaron Schock.

The financial chief for the House, Traci Beaubian, and three other staff members wrote letters notifying the chamber about the subpoenas that were read on the House floor Monday, the Chicago Tribune reported  based on House records noting the letters were received and video of the letters being read. The letters did not mention the subject of the subpoenas.

Schock, the one-time rising GOP star from Peoria, came under intense scrutiny in early 2015 for his spending, including redecorating his office in the style of TV's "Downton Abbey." He left office in March 2015 amid questions about congressional and campaign spending.

He has since been issued at least two grand jury subpoenas seeking campaign and congressional records. FBI agents also have removed boxes and other items from his central Illinois campaign office.