If the D.C. Police are not going to make that video available than why have the officers where the cameras?
The reason to have the cameras is to show the public, the People paying the checks. what the Police are doing on a daily basis, for the good or the bad. Hopefully for the good.
Those cameras should be tamperproof and should be running at all times while the officer is on duty except for those times when he needs a personal break. When that occasion occurs the officers immediate supervisor can deactivate the camera and then reactivate it after the break has ended.
The video would not be subject to FOIA requests, but WOULD be available by court order (such as when the cop is a party to a criminal or civil case).
In cases where the video is "unavailable" due to "malfunction", the jury should be so informed, the opposing attorney should be able to cross-examine as to the reason for the "malfunction", and the jury should be allowed to form an opinion as to whether they think the lack of video was a deliberate attempt to suppress evidence.