D.C. Code § 1-626.02: Retirement systems.

Existing retirement systems, which include the Civil Service Retirement System (Chapter 83 of Title 5 of the United States Code), Teachers’ Retirement System, Police and Fire Retirement System, Teachers’ Insurance and Annuity Association programs, and the Judges’ Retirement System, shall continue to be applicable to all employees except that the Civil Service Retirement System pursuant to 5 U.S.C. § 8331 shall not be applicable to employees first employed after September 30, 1987.