Page 89 - Automated Fingerprint Identification Systems (AFIS)

74 AUTOMATED FINGERPRINT IDENTIFICATION SYSTEMS

Figure 4.1
Computerized
AFIS Databases Criminal History
Database

Tenprint Latent Cognizant Unsolved Latent
Database Database Database

Why are there so many different databases? This depends on the purpose of
the AFIS, advances in technology, cost, size of the database, etc. AFIS systems
used exclusively in civil applications, such as for social services benefits, only
need a one-record database. In this type of use, as people become eligible for
benefits, they are enrolled in the database, which may contain images of
only the two index fingers or the two thumbs. This type of search is fairly
straightforward.
A brief note on the identification process is in order. Identification systems
match finger image characteristics, not persons. When a person is arrested and
fingerprinted, an AFIS search is conducted. If there is no match based on the
finger image characteristics stored in the database (see Fig. 4.2), the record is
assigned a state identification (SID) number. The CCH for the subject would
include his or her name as it appears on the tenprint record or as it appears
in the On-Line Booking System (OLBS), a computerized method of collecting
and forwarding arrest history and information.
If the same person is arrested again but presents a different name, the CCH
will return an identification with a criminal history that shows another name.
That is, the finger images of the person now in custody match a person with
another name, which means that both names belong to the same person. The
arresting agency will have to determine which identity, if either, is correct. In
the past, clever recidivists could use this ploy with some success, since not all
of the criminal history searches were fingerprint based. This loophole is quickly
closing as AFIS systems become more powerful and connected.
The tenprint (TPid), or identification, database contains the image record
characteristics that are used for searching. There may be the records from
two index fingers, the two thumbs, or other combinations. Some AFIS systems
combine the index fingers and thumbs in their tenprint searches. The latent
cognizant (TPlc), or criminal, database contains the finger image characteris-
tics of all ten fingers. The image captures as much image characteristic infor-
mation as possible, such as that contained in the nail-to-nail roll. The quality
of these ten images is important, since they are associated with arrestees who
may not be cooperative at the time the images are taken. For searching latent
prints found at a crime scene, the need for a database that contains all ten
images, of superior image quality, in a nail-to-nail roll, is readily apparent.