DES MOINES — A special investigation by the state auditor’s office has concluded an employee in the Iowa Department of Human Services filed more than $10,000 worth of improper or unsupported travel claims.Social worker Bobi Miller worked out of the agency’s office in Dallas County. Auditors reviewed the travel claims and work records she submitted over a nearly three year period. The auditor’s report concludes Miller claimed excess mileage for some destinations, didn’t have supporting records for other trips and had claimed reimbursement for work-related travel on days she was out sick or on vacation.Last April, Miller asked the agency’s director to pay her more than was allowed annually for travel. That sparked an internal review of her travel claims. Miller was placed on administrative leave last May. She resigned from her job last summer.Copies of the state auditor’s report have been filed with Des Moines Police and the Polk County attorney as well as the state attorney general and Iowa Division of Criminal Investigation.