WASHINGTON — New, computerized technology introduced in California and other states has vastly enhanced the usefulness of fingerprints in criminal identifications and seems to have started a downward trend in crime statistics, a Justice Department agency reported Sunday.
The Bureau of Justice Statistics said in a 20-page report that automated fingerprint identification systems (AFIS) not only have improved the accuracy of fingerprint identifications and reduced from hours to minutes the time it takes to run checks on prints, they have sharply increased the usefulness of latent prints left at crime scenes.
"Law enforcement officials believe that the AFIS systems not only are helping to solve crimes that otherwise would not have been solved, but are putting chronic offenders in jail and halting repeat offenders," the report said.
Tough Cases Broken
The use of modern forensic chemistry with computerized identification methods has broken some tough cases, according to the report. It said such a procedure facilitated the Orange County sheriff's investigation of the 1985 "Night Stalker" serial murders by aiding in the identification of latent prints left in a car, and that when an FBI laser detected a print left on a postcard nearly 40 years ago, AFIS quickly linked it to a Nazi war criminal.
San Francisco officials say that city's two-year-old AFIS system has been a factor in the convictions of 900 burglars and a subsequent 26% drop in the burglary rate, the report said. It said use of the system in the first year produced 1,001 identifications in 5,514 searches of latent prints and, as a result, solved 816 cases, including 58 homicides. A year earlier, it said, San Francisco police cleared only 52 cases on the basis of latent fingerprints.
California is developing a statewide network, known as CAL-ID, operated by the state Justice Department, in addition to the Los Angeles and San Francisco systems.
Sgt. Joseph Mussara, watch commander in the records and identification division of the Los Angeles Police Department, said in a telephone interview that the city's $6.5-million system is "up and operating, and we expect it to have an impact."
"The old way was like the Wright brothers' flight and the new way is like landing on the moon," Mussara said.
He said that about 300,000 out of 2 million fingerprints in the police files have been transferred to the computerized operation. They are being shifted on the basis of age, with priority given to younger subjects because young people more frequently are involved in crimes, he said.
AFIS was developed out of a long-term program started in the early 1970s to automate the FBI's identification division. Alaska and Minnesota also have state systems, and 15 other states expect to have them in operation by the end of this year.
Fingerprints have been used throughout the 20th Century as identification tools, but the process was slow and not always accurate. It depended on intricate classifications of the types of loops and whorls on the skin, and positive identifications required careful scanning by experts. The work slowed as the files grew. The FBI now has 23 million criminal fingerprints on file and California has 7.5 million in its state repository, according to the report.
The computers can scan fingerprints and record and store their details for later references in matching. With files of professionally rolled prints of all 10 fingers, the report said, the computers can search as many as 600 prints a second, and can go through 500,000 prints in a matter of minutes. With latent prints, which may be fragmented or blurred, search time averages half an hour, it said.
Procedure of Evidence
No final identification is made until trained fingerprint technicians compare the file prints with samples. To make fingerprint evidence stand up in court, the technician must prove through detailed comparisons that a police specimen is identical to a file print. On full, 10-print searches, the report said, the accuracy of computer matchings has averaged between 98% and 99%, against 60% to 74% accuracy with manual systems.
Latent prints are found at 35% of all crime scenes, the report said, but before AFIS, criminal identifications were made in less than 9% of the cases in which prints were found. Under standard procedures, smooth surfaces were dusted for prints, but it was difficult to find prints on porous surfaces, which absorb moisture and salts left by the fingertips.
Modern chemical and laser techniques have improved such results. One chemical, ninhydrin, is effective in bringing out prints left on paper. Cyanoacrylate, a gas emitted from super-glues, attaches itself to the chemicals in fingerprints and turns them white. To contain the gas, police enclose areas being tested for prints. In the Night Stalker case, for example, Orange County sheriffs sealed off an automobile with plastic sheeting.
Staff writer Lee May contributed to this story.