Mo. Rev. Stat. § 552.070
In the exercise of his powers under Article IV, Section 7 of the Constitution of Missouri to grant reprieves, commutations and pardons after conviction, the governor may, in his discretion, appoint a board of inquiry whose duty it shall be to gather information, whether or not admissible in a court of law, bearing upon whether or not a person condemned to death should be executed or reprieved or pardoned, or whether the person's sentence should be commuted. It is the duty of all persons and institutions to give information and assistance to the board, members of which shall serve without remuneration. Such board shall make its report and recommendations to the governor. All information gathered by the board shall be received and held by it and the governor in strict confidence.
§ 552.070, RSMo