Rep. Aaron Schock is resigning his seat at the end of the month in the wake of a congressional ethics investigation and looming federal investigation. The ethics investigation will focus on his use of taxpayer money, including mileage reimbursements from a car paid for by his campaign account.

Federal prosecutors in Illinois will focus on the mileage reimbursements as well as travel paid for by donors and in-kind contributions never reported.

Gov. Bruce Rauner must set a special election date within five days of Schock’s resignation at the end of the month; the congressional seat must be filled within 120 days.