DES MOINES, Iowa (AP) – The state auditor says 13 private attorneys working as public defenders overbilled the state by roughly $310,000 during a three-year period. Auditor Mary Mosiman released the report Thursday. Her office reviewed data from July 1, 2009, through Aug. 31, 2013, at the request of the State Public Defender’s Office. The report says 11 of the attorneys billed for work days that were longer than 12 hours. In some cases, they claimed to work more than 24 hours in a day.

A total of 13 attorneys filed improper mileage claims. State Public Defender Sam Langholz says contracts have been canceled with eight attorneys. Another attorney voluntarily terminated his contract. Langholz says the office has adopted new oversight rules.

A Department of Public Safety spokesman says the matter is under investigation.