The county legislative body has discretionary authority to establish the position of medical investigator to assist the county medical examiner. Generally, this position must have one of the following qualifications: a licensed EMT, paramedic, registered nurse, physician's assistant or a person registered by or a diplomat of the American Board of Medicolegal Death Investigators; and the person must be approved by the county medical examiner as qualified to serve. If a county has a coroner elected by the county legislative body, then the coroner acts as the medical investigator if the coroner is qualified, but if the coroner has served for 10 years or more the coroner is not required to be otherwise qualified. If the position of medical investigator is established and the coroner is not qualified to serve as medical investigator, then the county legislative body must either authorize the county medical examiner to appoint someone subject to confirmation of the county legislative body or provide for this function through a contract for service approved by the county medical examiner and the county legislative body. The county medical investigator may conduct investigations of possible unnatural death under the supervision of the county medical examiner and may make pronouncements of death but cannot sign a death certificate. The medical investigator may recommend an autopsy but cannot order one unless this authority is delegated to the medical investigator by the county medical examiner. T.C.A. § 38-7-104(f).