Mo. Rev. Stat. § 473.550
All interest received by executors or administrators on debts due to the decedent are assets in their hands. They shall not use the money of the decedent for their own private purposes. If they do so, they shall be liable to the estate for interest and any loss of principal. The deposit pursuant to section 473.337 of funds of the estate in the banking department of a banking institution which is the sole or joint executor or administrator may, however, be made in all cases in which such deposit would have been proper if such banking institution were not an executor or administrator of the estate. The court, at each settlement, shall exercise an equitable control in making executors and administrators account for interest, and for that purpose may take testimony or examine the executor or administrator on oath.
§ 473.550, RSMo