(5) Sheriff--an officer who is the chief executive officer of the county; he and his assistants, called deputies, form the county police force; the Sheriff serves warrants of arrests, summons witnesses and jurors whenever necessary, preserves peace in the county, has charge of prisoners, cooperates with the State Police and acts as a Bailiff at meetings of the Board of Supervisors and at Trial Justice and Circuit Court sessions; he is elected for a four-year term. Other significant county positions include County School Board members, County Superintendent of Schools, County Health Board members, County Surveyor, Welfare Board members, Planning Commission and Highway Commission members, Game Wardens and Election Board members. A state official who exerts strong influence upon the county is the State Circuit Judge. Since he tries cases in various counties within his own circuit, he comes in contact with many county officials and has the authority to appoint certain county officials within his own circuit such as (1) a Trial Justice who tries the less important civil and criminal cases in the county and holds hearings of cases to be tried by the circuit judge and (2) the Coroner who makes investigations and reports concerning sudden, violent or suspicious deaths in the county. The Circuit Judge also appoints the School Trustee Electoral Board which in turn appoints the County School Board. There are three types or forms of County Government in existence in Virginia: the County Executive Form, the County Manager Form and the County Board (often called the "Traditional") Form. Two counties, Albemarle and Fairfax, have adopted the County Executive Form and two counties, Arlington and Henrico, have adopted the County Manager Form. Arlington County was the first county in the United States to adopt the County Manager form of government by popular vote (1932). The major difference between the County Executive and the County Manager Forms of government is found in the fact that, in the former type, the Board of Supervisors makes all key appointments upon the recommendations of a county executive who is employed to act as the administrative head of the county whereas, in the latter form, the Board of Supervisors employs a manager for the county and gives him authority to name and appoint his own department heads. The remaining 94 counties are operated under a County Board: under this form, the Board of Supervisors exercises not only legislative but full executive authority as well. The county form of government, therefore, acts not only as a local government unit but also as an administrative agent of the state.