Background
Nearly every legal constraint on the collection and presentation of forensic or testimonial evidence in a federal criminal proceeding emanates from the 4th and 5th Amendments, and is applied to state-level cases by the 14th Amendment. Case law has not only affirmed the applicability of these constitutional rights; it has provided and continues to provide definitions, exceptions, and direction. Most importantly, the courts have shaped the “exclusionary rule” as the consequence for violation of these protections. The criminal investigator must have a comprehensive knowledge of these court decisions, the principles in which they are grounded, and their application to the investigation at hand.
