Del. Code tit. 9, § 1409

At the close of each fiscal year, the County Council, in accordance with County procurement laws and upon advice from the Audit Committee, shall cause a person or persons, certified by the laws of the State to practice accounting and not an employee of the County, to make a post-audit of the financial affairs of the offices, agencies, departments and boards of the County and of the procedures and practices of the County Auditor.