Tennessee Code Title 40. Criminal Procedure § 40-15-104

(a) Upon stipulation of the parties, the trial court by order may direct any county, municipal or authorized private agency, available for this purpose, or the department of correction if no local agency is available, to conduct an investigation of the defendant's background. In counties having a metropolitan form of government and in counties having a population of over six hundred thousand (600,000), according to the 1970 federal census or any subsequent federal census, the county, municipal or authorized private agency shall conduct any investigation of the defendant's background, but, this sentence shall be implemented within the existing level of funding to the department of correction. The order shall specify the purpose and scope of the procedure and the matters to be covered, and shall direct that the results of any investigation be embodied in a written report, copies of which shall be made available to the parties.

(b) In counties where there is a pretrial release program in operation, the agency responsible for the operation of that program shall be the agency to conduct the background investigation ordered by the court, and the order shall so stipulate. In counties which have a local county probation officer paid for by local funds, the county probation officer shall be the agency responsible for conducting the background investigation as ordered by the trial court.