A primary component of the investigative process is the identification of the suspect. However, various methods or procedures in the identification process, such as fingerprinting, photography, lineups, and dental examinations have been challenged on the constitutional grounds of self-incrimination, right to counsel and due process, and violations of the Fourth and Fifth Amendments. This chapter reviews the basis for these challenges. In addition, voice exemplars, a technique for voice identification, are seen as in compliance with constitutional provisions, but not sufficiently reliable. DNA profiling for identification purposes is recognized as adequately reliable and admissible in court, as long as all constitutional standards in sample retrieval and in laboratory standards are followed.