David B. Harrison
Many Officers now have Body Cameras or Dash Cameras - This often helps the defense
Many police agencies are now equipping their officers with body worn cameras or dash cameras in their patrol vehicles. For the dash cameras they can be turned on in one of three ways - manually when the officer wants to, when the car exceeds 55 miles per hour, or when the "emergency lights" are activated. The cameras are on a continual loop so you get the 30 seconds or so prior to the camera actually being turned on. Most of the time there is also a camera showing the seat a person is put in once they are arrested, so their actions can be seen as they sit in the partrol car after arrest.
Body worn cameras must be activated by the officer. They also have a moot button, and many officers arr getting good at turning off the audio when they choose to (like when the confer with another officer, etc.). Still, the existence of this video of the officers interactions with people - including the person accused of a crime - can clarify things. At times that helps the prosecutors, at times it helps the defense. An essential part of criminal defense these days is obtaining and reviewing the videos from a dash camera and / or body camera.