Indiana is hiring an international accounting firm for an audit of how the state lost track of more than $500 million in tax revenue it had collected.The State Budget Committee announced the hiring of Deloitte LLP Monday.The firm will likely brief state budget officials in July on the scope of the audit that's needed. Officials say the external audit won't start until after that briefing.The review follows the disclosure in December that $320 million in corporate tax money the Department of Revenue collected over several years hadn't been properly deposited in the state's general fund.State officials then announced in April that $206 million in local income tax revenue had been mishandled and not distributed over the previous 14 months to Indiana counties.The latter discovery prompted the resignation of Indianaβs revenue commissioner. (Information for this story came from the Associated Press)