Im a fan of first 48 too, good show. Most of those dead are less than stellar citizens but quite a few are completely innocent people who were killed by a dirtbag.
Home cams, small businesses, etc A LOT don’t have working systems or parts of the system are not working. When you get into larger gas station chains, Home Depot, lowes, Walmart, etc those systems are almost always working but often the distances are too far in exterior cams to see detail beyond the general incident.
I love the wanttabes who post pics of themselves with guns which are ID’d as the likely murder weapon. Even before FB, instagram, etc is cell phone location data and text messages. The shooters always have their phones and subpoenaed phone records put them feet from the crime scene at the time of the shooting. In the interviews the perps always put themselves across town so the cell data shows their a liar about that and kills their credibility on all of it.