D.C. Mun. Regs. tit. 17, r. 17-2006
A private detective license shall only be issued to a person who is not a resident of the District if the nonresident, as a condition of the license, appoints or employs an attorney-in-fact or general agent who is a resident of the District or who maintains an office in the District. Each nonresident licensee shall notify the Mayor of the appointment or employment of an attorney-in-fact or general agent.
The nonresident licensee shall also notify the Mayor, within five (5) business days, of any change in the appointment or employment of the attorney-in-fact or general agent.
In all cases of a nonresident licensee, notice of any action to be taken with respect to the license issued to that licensee may be served upon the attorney-in-fact or general agent appointed or employed by that nonresident licensee.
D.C. Mun. Regs. tit. 17, r. 17-2006