16 Pa.C.S. § 14929: Settlement of accounts on extraneous proof.

If any person in possession of books, vouchers or papers relative to public accounts before the controller or auditors refuses to produce the documents, or if any officer whose accounts are to be settled and adjusted by the controller or auditors refuses to attend or submit to examination, the auditors or controller shall proceed, by the examination of witnesses and other evidence, to ascertain and settle the amount of public money received by the officer and its application to public purposes.