Although the technology of fingerprinting and its use in the system originated in the United Kingdom, the place that played a great role was in the United States. In 1924, two large fingerprint databases in the United States were merged into the core of the archives currently held by the FBI’s identification office. . By the end of the 20th century, there were more than 90 million fingerprints stored in this office. Fingerprint files and retrieval technologies have been computerized, making it much faster to compare and identify specific fingerprints than before.
Other "fingerprinting" techniques have also been developed. These techniques include the use of sound spectrographs—a device that graphically depicts sound variables (such as frequency, duration, and intensity)—taking sound images or sound waves, and using a technique called DNA fingerprinting. It is a method of analyzing each person's DNA in different ways to identify material evidence (blood, semen, hair, etc.) belonging to a suspect. The latter assay has been used in parental identification tests and forensics.