D.C. Mun. Regs. tit. 17, r. 17-2101
No investigation or certification under this chapter shall relieve any security agency or other employer of the duty to investigate and make its own determination of an applicant's suitability for employment as a security officer.
All security agencies and employers have an affirmative duty to supervise security officers in their employ, and any attempt at a contractual limitation of liability shall be null and void.
In all cases, the liability of the security agency or other employer for the acts of its employees shall be limited to those times when the employee is on duty and to those acts within the scope of the employee's assignment or employment.
Failure of a private detective agency or security agency to properly supervise the activities of its employees is grounds for denial or suspension of the agency's license.
D.C. Mun. Regs. tit. 17, r. 17-2101