With her policeman husband sleeping upstairs, Debbie Smith was baking a cake in the kitchen of her Williamsburg home in March 1989 when a man grabbed her around the neck, forced her into the woods behind her home and raped her.

For the next six years, Smith lived in fear that her assailant would return. And then one day in 1995 her husband, Robert, came home from work as a lieutenant in the Williamsburg police department with the news she had been waiting for: DNA tests had identified her attacker and he was already in jail for unrelated convictions. The man was sentenced to three life terms in Smith's case, without the possibility of parole.

DNA, Debbie Smith said, "gave me my life back. I don't have to live in fear anymore."

The attack on Smith is one of 60 cases that have been resolved since 1993 through the use of a database of DNA samples collected from Virginia felons. With 70,000 DNA samples, Virginia now has the largest such database in the country.

As a result, the pace of matching DNA from crime-scene evidence with DNA samples stored in a computer in Richmond has increased markedly. Twenty-nine of the perpetrators were identified in the first six months of this year.

Virginia collects DNA samples from all convicted felons, including nonviolent offenders and juveniles whose crimes would be deemed felonious if they had been tried as adults. The result is that Virginia has collected 190,000 blood samples, a figure that is growing by 20,000 annually. (In contrast, Maryland has collected 3,700 blood samples and has placed 1,200 in its database; the District does not collect samples.)

Under a three-year, $9 million contract with Bode Technology Group Inc. of Springfield, the state has been adding 2,000 DNA samples to the database each week and plans to clear the backlog of 120,000 samples within the next two years.

"If you limit your statute to sex offenders and violent crimes, you'd have half of the hits we have so far," said Paul Ferrara, director of the Virginia Division of Forensic Science. "Based on our results, a lot of states are realizing they cast their laws too narrowly. They're looking to modify their laws."

Six Virginia inmates challenged the state's blood sample collection law in 1990, but it was upheld by the Fourth U.S. Circuit Court of Appeals, and the Supreme Court declined to hear an appeal.

Five years ago, Jackie Crumity, 33, had the dubious distinction of becoming the first person convicted in Virginia through the use of the nascent database. He had been convicted in the 1979 rape of a Prince William County woman and had a DNA sample taken while in prison.

Four months after Crumity was released in September 1992, a 64-year-old Dale City woman was sexually assaulted in her home. The woman testified that her attacker had wrapped a torn curtain over her eyes and beat, kicked and raped her. The assailant later dragged her into a bathtub and attempted to wash away evidence of the attack.

Police had no physical description of the attacker and no fingerprints, but they found a semen stain on the woman's bedsheets. The DNA sample pinpointed Crumity as the assailant. He is serving a sentence of life plus 30 years.

"It shows the value of DNA technology," particularly in sexual assault cases, said Commonwealth's Attorney Paul B. Ebert, the Prince William County prosecutor. "They're awfully hard to prove. [The victims are] traumatized witnesses. Their testimony is subject to attack. Oftentimes this happens at night."

The database has been used to exonerate people as well as convict them -- sometimes both in the same case.

On July 11, 1994, Hope Denise Hall, a 22-year-old associate producer for a Richmond television station, was stabbed to death in her Petersburg apartment. Police charged an acquaintance who Hall's father, Tony Sievers, said had expressed interest in dating his daughter.

"The lab information came in shortly after that," Hall's mother, Carol Sievers, recalled. "The DNA showed he couldn't have" committed the killing.

More than two years later, a state forensic examiner made a DNA "cold hit," meaning that the suspect was unknown to police when evidence from the Hall crime scene was matched against DNA samples contained in the state's database.

The search pinpointed convicted rapist Shermaine Johnson, who was already serving a century-long sentence in two other rapes committed around the time of the Hall murder. He was convicted of the Hall slaying and is now on Virginia's death row.

"We thank God for DNA and the technology," Carol Sievers said. "It will help exonerate the innocent and convict the guilty. We want to make sure the right people are in prison."

Despite occasional setbacks for law enforcement officials in the use of DNA samples -- the O.J. Simpson case being the most prominent -- its role in solving crimes is likely to grow.

"The technology is moving exponentially," said Thomas J. Bode Sr., president of the Springfield firm that bears his name. The Bode firm and a San Diego company, Nanogen Inc., are developing a computer-chip apparatus the size of a credit card that in the next three years may further revolutionize police investigations in many cases.

Bode and Kevin C. McElfresh, the firm's vice president and director of research, said they envision police being able to put biological evidence from a crime scene directly onto the apparatus, which technicians then would be able to insert into a computer at the scene to check for a DNA match with any known criminal. "You'll be able to take blood off the sidewalk," McElfresh said, "put it in the chip, and it would be analyzed within minutes."

CAPTION: Thomas J. Bode Sr., president of Bode Technology Group of Springfield, displays a computer-chip device he envisions police using to do instant DNA checks at crime scenes.