A latent print examiner is a crime scene analyst who examines items for fingerprints and compares any fingerprints found against a central database. Latent fingerprints, which are impressions made by distinct ridges in the skin that become coated with sweat, are not often visible to the naked eye. Without exception, every person's fingerprints are unique and appear the same from 16 weeks of gestation until death unless severe injury occurs.
One of the main jobs of a latent print examiner is to utilize chemical and physical fingerprint identification techniques. Another part of the job is fingerprint analysis. A fingerprint examiner seeks to find the many distinct characteristics possessed by each and every fingerprint. Since there are over 100 unique identifiers per fingerprint, even a partial print may be considered fingerprint evidence. Latent prints may easily be smudged, wiped or affected by some course of events, making it a necessity for the examiner to have a keen eye and thorough understanding of the methods and technology used in this field of criminology.
Latent fingerprints can be made visible in a number of ways. Dusting with pigment, the use of chemicals such as ninhydron or cyanoacrylate vapors as well as inking are all valid methods that a latent print examiner may use. The method of visualizing a fingerprint depends upon a number of factors, including but not limited to the composition and sensitivity of the surface the prints are on, climate and the size of the object that is being examined for fingerprints.
Once these fingerprints are identified and analyzed, the criminologist may then begin comparing the fingerprints found to a database of prints, or prints taken from a person suspected of committing the crime. Fingerprinting a suspect includes pressing their fingers in ink and rolling them onto paper in a controlled, scientific manner. From there, the latent print examiner can scan the suspect's fingerprints into a computer and compare them with the prints found at a crime scene, thereby eliminating or confirming a suspect.
The qualifications for becoming a latent print examiner vary by location and place of employment. Within the United States, for example, it is generally accepted that work in this position, a person must have achieved certification through the International Association of Identification (IAI), which also has affiliates in more than a dozen other countries. Although different locations have different requirements for employment, certification through the IAI is accepted almost everywhere.