California is changing how it applies a new law allowing some parolees to go unmonitored after their release from prison, and will return 656 of the parolees to active supervision after learning they are at high risk of committing new crimes, prison officials said Wednesday.

Corrections Secretary Matthew Cate told The Associated Press that upgrades to a computerized risk-assessment program found that some parolees had committed more crimes than officials previously believed.

So far, 6,667 ex-convicts have been placed on non-revocable parole under the new law that took effect in January.

The improved computer program developed under contract by the University of California, Irvine, found nearly 10 percent were at higher risk than originally projected. The improvement means the computer program can more accurately read court files and police records, Cate said.

"It's got better data to make decisions now," Cate said.

The revelation means that 442 recent parolees who were not being monitored will be actively supervised. Another 214 who were set to go on non-revokable parole were also found to be at high risk of committing new crimes.

Those ex-convicts on non-revokable parole don't have to report to parole agents and can only be returned to prison for committing new crimes.

The AP disclosed last week that some of those released under the non-revocable parole program had been convicted of violent or threatening crimes.

Cate said he didn't know if any of those now deemed a high risk had been convicted of those crimes, though all are considered nonviolent, nonserious and non-sex offenders under the legal definition set by the law. The law was passed last fall to ease prison crowding while cutting an estimated $500 million from the prisons' budget this year.

The more rigorous computerized risk review will also be used for future parolees, Cate said.

Cate disclosed the decision a day after the AP filed a Public Records Act request asking about problems with the computerized program.

The department decided last week to change the status of the 214 recent parolees who were still being processed, he said.

It decided this week to retroactively change the status of the remaining 442 parolees previously placed on non-revocable parole, Cate said. The department is only now beginning to notify those individuals that they will be actively monitored by parole agents, typically for three years, and can be returned to prison for parole violations.

"It's something we're trying to do to be as conservative as we can on crime," Cate said.

He acknowledged parole agents may have trouble finding some of the parolees, and said reinstating the individuals to supervised parole may prompt legal challenges.

"This just seems like an ongoing fiasco that potentially continues to put the public at risk," said Sen. George Runner, R-Lancaster, a leading critic of the program. "These are individuals now who Corrections has signed out of any kind of supervised parole. They don't know where these individuals are. Now they're going to try to find them."

However, Nick Warner, who represents both the California State Sheriffs' Association and Chief Probation Officers of California, praised the department for deciding to take past probation violations and a broader criminal history into account.

"It really, really improves their ability to gauge risk," Warner said. "If there's a better way to do it, they're going to try to find it."