D.C. Code § 16-514
When a writ of attachment is served on a garnishee, and the garnishee holds a credit or property for two or more persons, including the person whose credit or property is sought to be attached, or holds a credit or property for a person as agent or trustee or in any other representative capacity without designation of the principal or beneficiary, the credit or property is not subject to withdrawal by any person, but shall be held by the garnishee until the attachment is dismissed or otherwise disposed of by the court. If the credit or property is condemned, payment or delivery thereof as ordered by the court is a complete discharge of the garnishee from all liability to any person in respect of the credit or property. The provisions of this section do not apply to a credit or property of a partnership.
D.C. Code § 16-514