It is hereby made unlawful for any of the funds of the county to be deposited in any bank in which the county treasurer or any member of the board of county commissioners is the owner of any stock or otherwise directly or indirectly pecuniarily interested. A county treasurer or county commissioner shall be considered to be interested in such bank if any member of his immediate family owns any interest in said depository bank.
Okla. Stat. tit. 19, § 123