The database, known as the Combined DNA Indexing System or CODIS, has helped solve two "cold" murder cases in Kansas, identify the two-decade old remains of a missing California child and capture a sexual predator who terrorized young boys in Houston.

Just as important, police and lawyers say, it has freed prisoners wrongly convicted of crimes and helped detectives quickly eliminate wrong suspects, saving manpower chasing false leads.

"This basically is the fingerprint technology of this century," said Joseph M. Polisar, the police chief of Garden Grove, Calif., and the president of the International Association of Chiefs of Police. "The potential for us in the criminal justice field to solve crimes with this technology is boundless."

As a side benefit, the sharing of genetic fingerprints also has helped the FBI improve relations with local law enforcement, which for years was frustrated by problems with information sharing, Polisar said.

The FBI says more than 8,000 samples of genetic evidence from unsolved cases have been matched to past or current convicts in the database, helping to solve crimes. An additional 3,000 samples have been matched to unidentified suspects in other cases that remain unsolved, creating links between cases.

The FBI lab was struck by controversy over shoddy work and exaggerated or false testimony by its scientists in the 1990s, but its current director, Dwight Adams, has addressed those issues and made a priority of expanding the DNA database.

A DNA scientist by trade, Adams acted to insulate the DNA database from legal or scientific attack. His lab created a sophisticated identification system to safeguard the privacy of samples and ensure matches are double-checked before suspects are arrested.

"The process doesn't stop just because you make a match to an individual in the database," Adams explained in an interview. "The next stop in the process is for the law enforcement agency to obtain a warrant, get a blood sample from the same individual and do the same testing to ensure there is a match."

CODIS has gathered genetic samples from more than 1.6 million criminals, most taken after they entered prison. The database also includes more than 80,000 DNA samples gathered from unsolved crime scenes. Each month, between 10,000 and 40,000 new samples are added by local authorities.

The database started in the early 1990s as a trial and was expanded to 50 states in the late 1990s. Now, at least 170 local crime labs across the country can run DNA samples through the database and find matches.

One of the database's more dramatic successes occurred in Houston last November when the FBI matched DNA evidence to help capture a bike-riding sexual predator who assaulted young boys at knifepoint.

The case had stumped authorities for months, forced many parents to keep their children inside before the database was used to match DNA from a victim to a known sexual offender in CODIS.

Other successes:

• In Wichita, police were able to crack two old murder cases by finding DNA matches to prisoners. One was charged for the 1995 murder of an elderly woman; the other was charged in a fatal stabbing.

• Authorities in Massachusetts were able to charge a convicted murderer last summer in the 1998 death of an elderly Foxboro woman who was stabbed 29 times.

• Police in California cracked the case last year of 16-year-old boy who disappeared in 1982. A man pleaded guilty to manslaughter after the FBI was able to extract DNA from headless skeletal remains and matched it to the missing boy's mother, confirming the victim.

CODIS also can affect the wrongly convicted. Lawyer Barry Scheck and his Innocence Project have used DNA to help free more than 100 prisoners.

Defense lawyers, though concerned about some privacy issues, applaud the FBI's efforts and say they want the lab to make DNA science irrefutable, increasing the current 13 markers used for matches.

"Any mechanism which increases communication and cooperation between law enforcement agencies is a good idea. What we especially value or encourage ... is an increased reliance on scientific evidence over more traditional and less reliable forms of proof," said Steve Benjamin, a Virginia lawyer who co-chairs the National Association of Criminal Defense Lawyers' committee on forensic evidence.

When Adams joined the team of six FBI analysts and technicians that started the FBI's DNA section in 1988, it took six weeks to get police test results. Today, there are 100 scientists on the FBI's DNA team and technology has shortened testing to as little as 24 hours.

"If we can get this down to a few hours or less, we will improve all the more because there are still more cases and more samples that can be worked," said Adams, the first FBI scientist to testify about DNA in court.