Actually what I find most awful about CSI shows is the notion that police investigations are akin to unbeatable magical formulas. If investigators zero in on a suspect, almost inevitably that suspect is guilty, and found to be so by incredible technologies used by beautiful people in sci-fi like laboratories. Even in slightly more realistic portrayals of criminal investigations, like the original Law And Order, seldom is the accused actually innocent, but rather he or she manages to elude justice through some combination of sloppy police work and prosecutorial errors.
But even worse than all those cop and CSI dramas to my mind are the police investigation news magazines like 48 hours, where the police zero in on a suspect, arrest him, and the prosecutors successfully see the accused right through conviction. They usually pay lip service to the notion of the presumption of innocence by allowing the inevitably evil convict to assert "I'm innocent!", though with a weary and bemused postscript by the narrator indicating that justice was done, the cops always get their man, and the DA is godlike in his or her ability to convince a jury of guilt.