SAPD's AFIS system consists of two full-service work stations, three verification stations, and four "live-scan" (inkless) finger printers, all connected to three RISC 6000 IBM computers and a Model 900 Optical Disk box. High-capacity magnetic and optical disks are used for electronic storage of fingerprint images and their identifying information. The computers running specialized software carry out the matching and data processing functions. The system has a maximum search capacity of 600,000 ten-print cards and 50,000 unsolved latent prints. The AFIS system at SAPD is manufactured by North American Morpho, and was purchased through asset seizure funds.

Fingerprints, the pattern of ridges and curves unique to each human being, have been an important tool for law enforcement since the early years of the 20th century. Recognition that each person has a unique fingerprint "signature", made it possible for police to identify suspected criminals by matching the trace evidence left by the contact of a finger pad with any surface (including paper) with the print pattern on the finger pad(s) of a suspect. Fingerprints have been admissible as evidence in criminal trials since the early 1900s. The FBI consolidated several national criminal and fingerprint identification functions into the FBI Identification Division in 1924. The San Antonio Police Department established its Identification Unit in 1925.
Until very recently, all fingerprint identification was done visually (manually), by trained specialists, who classified and categorized literally hundreds of thousands of fingerprint records, both "ten-print" cards (cards with ink-prints of the ten fingers of a known person) and "latent-print" cards (partial or individual prints lifted from a crime scene). Although prints were classified and filed according to three major groups (arch, loop and whorl) and many sub-groups (a classification system first developed by Sir Richard Henry), the process of manually locating and visually matching crime-scene prints to known-suspect ten-print cards (or vice versa) was both time consuming and subject to omission or oversight.

SPEED: The Identification and Latent Fingerprint Unit of the San Antonio Police Department estimates that to conduct a manual latent fingerprint search against the fingerprint cards on file before AFIS was put into operation would have taken one person about 50 years, working 24 hours a day, seven days a week. Now AFIS can do the same search in a matter of minutes. Prisoners can be printed and the files searched in a matter of seconds.

SCOPE: For years, latent fingerprint evidence had been logged and filed away due to the lack of a suspect. Since the introduction of AFIS in May of 1996 the department has been able to identify more than 500 latent prints on cases where no suspect previously existed. The earliest latent print identification was made on a murder case from 1969.

CASE EXAMPLE: The following is an example of a case in which AFIS provided an identification where manual fingerprint searches had not been productive.
In May 1989 an elderly gentleman was murdered at his home in the northeast part of San Antonio. It appeared that the victim came home and was surprised by his attacker. The crime scene was processed and it was discovered that a light bulb had been unscrewed from the front porch light. Fingerprints were developed and lifted from the light bulb and then sent to the Latent Fingerprint Unit where they sat in the file for eight years with no suspect. In September of 1996 those latent prints were entered into the AFIS system and a suspect was immediately identified. Because of AFIS the SAPD Homicide Unit has been able to identify and file charges on the suspect. This would not have come about without the use of AFIS.