I don't mean to answer this question for Richard, and I'm not generally a watcher of Dateline and shows of their ilk, but it seems to me that the few times I happen to catch one of these shows on TV, they are only highlighting crimes where the case has been already been tried to a jury. The shows structure seems to be to present first the prosecution's case and then the defense's case through re-enactments, footage of the crime scene and crime scene evidence and then to "announce" the jury's (possibly surprising) verdict (or perhaps the appeals court's ruling) at the end. They don't actually engage in any "sleuthing" of their own (relying instead on the lawyers and court record to spoon feed them) and, it seems to me, are too lazy to actually investigate a case that hasn't been prosecuted.
