The criminal records system California relies on to stop child abusers from working at schools and violent felons from buying guns is so poorly maintained that it routinely fails to alert officials to a subject's full criminal history.

The computerized log exists to provide an instant snapshot of a criminal past, informing police, regulators and potential employers of offenses such as murder, rape and drug dealing in a person's background. But nearly half of the arrest records in the database don't say whether the person in question was convicted.

Information from millions of records buried at courts and law enforcement agencies has never been entered in the system. So a small army of state employees must spend precious time - and millions of dollars each year - chasing paper records to fill in the gaps.

The resulting delays often make it impossible for a police officer to learn immediately whether a driver he or she has pulled over is a convicted felon, or let a gun-shop owner know if it's safe to hand over a weapon.

"There are obviously serious public safety implications if that database is incomplete," said Dennis Henigan, president of the Brady Center to Prevent Gun Violence, a national gun-control group. "Every record missing from the system could be someone who is too dangerous to buy a gun."

California has a shoddy system for collecting case results from 58 county courts and hundreds of local prosecutors and police agencies, said Travis LeBlanc, a special assistant attorney general who oversees technology operations in the state Department of Justice.

The final outcome -- guilty, not guilty, case dismissed - is missing for about 7.7 million of the 16.4 million arrest records entered into state computers over the last decade, according to LeBlanc. More than 3 million of those are felony arrests.

Last month, California's inspector general estimated that 450 inmates who had completed their sentences but were still "a high risk for violence" had been released without supervision from parole agents. In some of those cases, prison officials relying on the faulty database didn't know the inmates had previous convictions and were supposed to be strictly supervised.

The data hole persists despite more than $35 million in federal grants the state Justice Department has received since 1995 to help plug it, according to department records. And a project to modernize court computers that began in 2001 is still not finished, even as its cost has ballooned from $260 million to as much as $1.9 billion, according to a state audit earlier this year.

"This is completely unacceptable," said state Sen. Kevin De Leon (D-Los Angeles), a longtime critic of the state's underperforming computer contracts. "This is about public safety here. There's no excuse."

In an interview last week, state Atty. Gen. Kamala Harris said she had spoken with Chief Justice of California Tani Cantil-Sakauye about the longstanding problem with the crime data. The two - who have been in their positions for less than a year - are looking for ways to bring the computer system into the "21st century," Harris said.

The information missing from the state Justice Department's Automated Criminal History System usually takes two to three weeks to obtain but can take even longer, officials said. And the problem doesn't affect only background checks done in California. The state's data are also used by the FBI in criminal checks for gun stores, employers and licensing authorities across the country.

Although California has a 10-day waiting period for gun purchases, and officials say they can stall longer if they still don't have answers, most states have a three-day waiting period. In those states, if a background check isn't complete by the end of the third day, the buyer can legally purchase a gun.

Some large retailers, such as Wal-Mart, wait until they get a final answer before selling a weapon, said Steve Fischer, spokesman for the FBI's Criminal Justice Information Services Division.

"But smaller mom-and-pops, they need that revenue, so they transfer the guns" as soon as the three days pass, Fischer said. If a conviction is discovered after that, the FBI turns the information over to the Bureau of Alcohol, Tobacco, Firearms and Explosives, and "they decide whether to retrieve the gun."

Operations to confiscate guns from people who should not have them are time-consuming, potentially dangerous and rarely a complete success, authorities acknowledge.

Last month California launched its own effort to round up 1,200 firearms from people whose records were clean when they bought the guns but who had since been judged mentally ill or had restraining orders issued against them. Although the roundup was hailed as a victory, officials acknowledge that they know of at least 34,000 guns - 1,600 of them military-style assault weapons - still in the hands of people prohibited from owning them.

Harris said in a statement that her department and local law enforcers don't have the money or manpower to collect them all.

The information delays vex the FBI as it performs background checks on millions of people applying for jobs in public safety or for positions in which they would be responsible for children, the elderly or sensitive financial information, Fischer said.

When conviction information turns up after a job has been filled, it's up to local authorities to decide what to do with it.

"If you're looking at a schoolteacher and they have a 15-year-old DUI, you might overlook that.... If it's a sexual crime, they may be more likely to pursue it," Fischer said.

A record is created in the California database any time someone is arrested and his or her fingerprints are taken. The disposition of the case, which may not be decided for months or years, is supposed to be reported to the Justice Department by the county court, district attorney or local police department.

Some agencies report dispositions electronically. Others send records in hard copy or even by hand-written note, LeBlanc said, causing long delays in getting the information into the computers. Some local agencies never report the outcome of a case - leaving what police call "naked" arrest records.

The state spends millions of dollars a year on labor as it tries to fill in the blanks.

"We have 60 full-time people who identify naked arrests and then seek to fix those histories," LeBlanc said. The employees call courts, send letters to prosecutors and query police departments to find the missing pieces.

Local law enforcement agencies are forced to do the same kind of leg work, and "you're not going to get answers right away," said Capt. Pat McPherson, an investigator for the Los Angeles County district attorney's office. "It takes a long time."