The agency of any county may appoint a commission for the purpose of examining applicants for the position of law enforcement officer, the administration of its civil service or merit rating system and for hearing and affirming or revoking the suspension or removal of any such officer. Such commission shall have three (3) members. Of the members first appointed, one member shall be appointed for a term of one (1) year, one member shall be appointed for a term of two (2) years and one member shall be appointed for a term of three (3) years. Thereafter all members shall be appointed for terms of three (3) years. The agency shall provide such commission with necessary personnel and shall by resolution prescribe the duties and compensation of such commission. Before entering upon the duties of their office each commissioner shall take and subscribe an oath to support the constitution of the United States and the state of Kansas, and to obey the laws and to endeavor to secure and maintain an honest and efficient force, free from partisan influence or control, and to perform the duties of his office to the best of his ability. Such oath shall be filed with the secretary of the agency.