We are a country of federal, state, and local laws (and international treaties, for that matter). So when someone asks, “What’s the Law On …,” law librarians and lawyers need to show laypeople how to Find the Law(s).
NPR has done that for you with Body Cam Laws (but, note that laws change so you will need to update this research each time you need accurate data.)
“Piecing Together America’s Patchwork Quilt Of Body Cam Laws,” posted 2/25/16, at NPR’s All Tech Considered.