District of Columbia Code
Chapter 5 - Counterclaims
§ 13–504. Action by trustee

When the plaintiff in a civil action is trustee for another, or has no actual interest in the contract on which the action is founded, a demand against the plaintiff may not be pleaded by way of counterclaim, but a demand against the person whom he represents or for whose benefit the action is brought may be pleaded.
(Dec. 23, 1963, 77 Stat. 516, Pub. L. 88-241, § 1.)
1981 Ed., § 13-504.
1973 Ed., § 13-504.