D.C. Code § 47-1804.02

The amount of all items of gross income shall be included in the gross income for the taxable year in which received by the taxpayer unless, under methods of accounting permitted under § 47-1804.01, any such amounts are to be properly accounted for as of a different period. In the case of death of a taxpayer on the cash basis, no amount will be accrued on his final return; and on the accrual basis, amounts (except amounts includible in computing a partner’s net income) accrued only by reason of the death of the taxpayer shall not be included in computing net income for the period in which falls the date of the taxpayer’s death, but such amounts shall be included in the income of the person receiving such amounts by inheritance or survivorship from the decedent.