D.C. defines a “dangerous” dog as one who has been trained to be vicious or has demonstrated behavior that threatens the public.
Dangerous dogs are impounded by the City until a licensed veterinarian has cleared them to be re-released to the owner.
D.C. does not establish any criminal punishment for the owner of a dangerous animal, but does hold owners civilly liable for any bites the animal inflicts.
Source: DC Consolidated Dog Laws