This is an MPD issue and can only be addressed by them unless the animal is being abused. If you feel the animal is in danger you will have to contact DC Animal Control.
Emergency and After Hours Information: Animal Care and Control Facility 1201 New York Avenue, NE Washington, DC 20002. 24 hour line: (202) 576-6664.
Or you can contact the Washington Humane Society
I've contacted MPD ~7 times already but all they are able to do is talk to the owner and ask her to put the dog inside. The last time I called (few months ago) I was told to stop calling because there is nothing more they can do. I don't understand how there are dog barking ordinances yet the police can't do anything.
If you havent done so already you may want to talk to the Commander in your Police District. The information can be found in the link below.
I feel your pain. Look up the noise laws in your neighborhood.