Fingerprints

Fingerprint comparison is a form of pattern identification. The history of fingerprinting in general goes back hundreds of years. Its use in the criminal justice context is more recent, but fingerprint comparison testimony has been admitted as evidence in criminal prosecutions in the United States for over one hundred years. Courts have accepted the proposition that each person’s fingerprint is unique and that fingerprint comparison is almost infallible as a means of forensic identification. Fingerprint experts often declare a “match,” a positive identification, even stating that it is “100% certain” that the defendant is the person who left a crime scene fingerprint. Indeed, fingerprint comparison has been referred to as the “gold standard” of pattern identification. In recent years, that assumption of infallibility has been called into question. There are documented errors stemming from unclear or partial prints, examiner bias, and system issues within fingerprint databases. In its present state, fingerprint comparisons may not be entitled to the great weight that criminal courts and jurors have long ascribed to it. Strides have now been made to improve fingerprint databases and move to a more probabilistic assessment of the likelihood that a crime scene fingerprint was left by a particular suspect or defendant.