Citizens for Responsibility and Ethics in Washington has filed a complaint against O'Donnell with the Federal Elections Commission and is asking federal prosecutors to investigate her.
The complaint is based largely on a sworn statement by O'Donnell's former campaign finance consultant, David Keegan. He says O'Donnell used campaign funds to pay her rent in both March and April 2009, then listed the spending as "reimbursement expenses."
The complaint also accuses O'Donnell of using campaign funds to pay for gas, meals and a bowling outing.
O'Donnell is a tea party favorite who upset longtime Rep. Mike Castle in Delaware's GOP Senate primary.