16 Pa. Stat. § 7375
He shall scrutinize, audit and decide on all bills, claims and demands whatsoever against the county, and all persons having such claims shall first present the same to the controller, and, if required, make oath or affirmation before him to the correctness thereof; he may, if he deems it necessary, require evidence, by oaths or affirmation of the claimant and otherwise, that the claim is legally due and that the supplies or services for which payment is claimed have been furnished or performed under legal authority; he may inquire or ascertain whether any officer or agent of the county is interested in the contract under which any claim may arise, or has received or is to receive any commission, consideration or gratuity relating thereto, or whether there has been any evasion of the tenth section of this act by making two or more contracts for small amount which should have been in one; and if he shall find that there has been any evasion or that any such officer or agent is so interested, he shall refuse to approve the claim; all claims which the shall find legally due he shall certify to the commissioners. He shall countersign all receipts given by the county treasurer to persons paying money into the treasury and keep an accurate record of the same.
16 P.S. § 7375