16 Pa. Stat. § 4950
The controller shall scrutinize, audit and decide on all bills, claims and demands whatsoever against the county. 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. The controller may, if he deems it necessary, require evidence, by oath 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 provisions of this act by making two or more contracts for small amounts which should have been in one. 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 he shall find legally due, he shall certify to the commissioners.
16 P.S. § 4950