In the fascinating world of medical discovery, the interpretation of how and when a person died can often be explained by looking at the bugs that are found on the body. Dr. Michael Baden, the Chief Medical Examiner for the New York State Police, is the author of "Dead Reckoning, the New Science of Catching Killers," and our guest in a two-part series on forensic pathology, the study and public discussion of how, when and where people died.