D.C. Code § 21-142

Within three months after the execution and approval of his bond, a guardian shall return to the court, under oath, an inventory of the real and personal estate of his ward and of the probable annual income thereof, and the court may direct the estate to be appraised and the annual income thereof to be ascertained by two competent persons, to be appointed by the court, who shall report their appraisement and finding under oath.