Many of these agencies began sending copies of their fingerprint cards to the National Bureau of Criminal Identification, which was established by the International Association of Police Chiefs. Some countries have set their own standards which do include a minimum number of points, but not in the United States. The National Bureau and Leavenworth consolidated to form the nucleus of the F.B.I. fingerprint files. With the introduction of AFIS technology, the files were split into computerized criminal files and manually maintained civil files. Many of the manual files were duplicates though, the records actually represented somewhere in the neighborhood of 25 to 30 million criminals, and an unknown number of individuals in the civil files.
Fingerprints offer an infallible means of personal identification.
That is the essential explanation for their having supplanted other methods of establishing the identities of criminals reluctant to admit previous arrests. Other personal characteristics change - fingerprints do not. In earlier civilizations, branding and even maiming were used to mark the criminal for what he was. The thief was deprived of the hand which committed the thievery. The Romans employed the tattoo needle to identify and prevent desertion of mercenary soldiers.