OKLAHOMA CITY (AP) — An embattled virtual charter school that has grown to become Oklahoma's largest public school used a "remarkably complex" infrastructure to divert tens of millions of taxpayer dollars into a for-profit business controlled by three men, State Auditor and Inspector Cindy Byrd said Thursday.

Byrd, a Republican with more than two decades of auditing experience, said the the problems uncovered in the investigative audit of Epic Charter Schools and the company that manages it, Epic Youth Services, were among the worst she has seen.

Byrd released a scathing 120-page audit of the...