D.C. Code § 16-1105

It is not a bar to the plaintiff’s recovery in an action of ejectment that the legal title to the property claimed is outstanding in another as mortgagee or trustee under a mortgage or deed of trust to secure a debt, unless the mortgagee or trustee, or those claiming under him, has taken possession of the premises, or unless the defendant claims under the mortgagor or grantor in the deed of trust.