By Bob Egelko, New York Times

SAN FRANCISCO -- Francisco Carrillo spent 20 years in prison for a murder conviction at age 15, then was released after all six eyewitnesses recanted their testimony and one described being coached by police investigators.

Kash Register, convicted of murder at age 18, was freed 34 years later after a judge ruled that prosecutors had withheld evidence that might have cleared him. Oscar Lee Morris spent 16 years in prison, six of them on Death Row, before the prosecution's main witness, who had been secretly promised leniency, admitted he had fabricated his testimony.

Their cases are among 692 felony convictions in California that were thrown out between 1989 and 2012 based on errors or misconduct by police, prosecutors, defense lawyers or judges, according to a new study by researchers at UC Berkeley and the University of Pennsylvania.

The report said that those cases cost taxpayers more than $282 million for trials, appeals, imprisonment and compensation for some former inmates -- but that the figure is probably just a small fraction of the financial impact of mistakes in the state's justice system.

It didn't include misdemeanor cases, which amount to about 80 percent of all prosecutions, or juvenile cases, because the state doesn't keep public records of their dispositions. And it also excluded the costs of jailing people who were later released without charges, which may amount to $70 million a year, the report said.

``We should be aiming for zero errors in our criminal justice system,'' said Rebecca Silbert of the Earl Warren Institute on Law and Social Policy at UC Berkeley Law School, a co-author of the study. ``The costs are too high to ignore.''

For Carrillo, now 42, the costs were 20 years that he'll never get back. He now attends college in Los Angeles, is due to graduate in May and hopes to work as a marital and family therapist.

``I went into this as a naive 15-year-old boy, knowing I was wrongfully accused and thinking justice would prevail,'' he said.

``Adults who were hired to do the right thing ... lying witnesses, misleading officers ... let me down.''

The study examined only records from California and drew no comparisons with other states. But, according to the National Registry of Exonerations at the University of Michigan, California, which recently was surpassed by Texas as the state with the largest prison system, ranks fourth among the states in the number of prisoners cleared of their criminal convictions since 1989, behind Texas, New York and Illinois.

The report looked at cases in which felony convictions were overturned and the defendants were later cleared, either because a jury acquitted them in a retrial or because prosecutors decided to dismiss the charges. About one-fourth involved cases in which the defendants had pleaded guilty, usually in plea agreements to avoid longer sentences, the report said.

One unexpected finding of the study was that violent crimes made up 18 percent of felony convictions in California in 2013, but accounted for 30 percent of the felony convictions that were thrown out during the previous 23-year period. The disparity could reflect the complexity of many prosecutions for violent crime, the emotion involved in those cases, or ``increased public pressure to achieve a conviction,'' the authors said.

Prosecutor misconduct was a leading reason for reversals. It accounted for 11 percent of the overturned convictions but 24 percent of the overall cost. That was more expensive than any other type of error, apparently because it often occurred in serious cases with long sentences -- 44 percent of the misconduct led to homicide convictions, the report said. It also said more than half the cases involved prosecutors' wrongful withholding of evidence that could have helped the defense.

One example was that of former Black Panther Elmer ``Geronimo'' Pratt.

Pratt was convicted in 1972 of murdering schoolteacher Carolyn Olson during a 1968 robbery in Santa Monica and was sentenced to life in prison, based in part on a fellow Black Panther's testimony that Pratt had confessed to him.

He was freed in 1999 after a judge found that prosecutors had withheld evidence that the witness was an informant for the FBI, which was then trying to discredit Pratt as part of its Cointelpro campaign. The judge also said prosecutors had concealed evidence that might have supported Pratt's claim that he was in Oakland when Olson was murdered. Prosecutors decided not to retry Pratt, who died in 2011.

The report said California has taken an ``encouraging first step'' to reduce prosecution misconduct with a new law requiring judges to report prosecutors to the State Bar if they intentionally withhold evidence they should have turned over to the defense. But the authors questioned long-standing laws that shield prosecutors from lawsuits by criminal defendants. They said they knew of no other profession that received immunity for ``intentional wrongdoing that gravely injures another.''

Other common problems cited in the study included faulty eyewitness identification, illegal searches -- particularly in drug cases -- and incompetent work by defense lawyers, such as failing to call crucial witnesses. In one such case, DeAndre Howard served 11 years of a life sentence for a 2002 shooting in Los Angeles that killed one man and wounded another. He was granted a new trial because his lawyer had failed to obtain testimony from the wounded man, who swore that Howard was not the shooter. Howard was acquitted at a retrial.

California provides state compensation for inmates who have been wrongfully imprisoned. But among the erroneous convictions covered in the study, only 58 people applied for compensation and just 14 have been granted compensation, totaling about $5 million, the authors said. They said the state Victims Compensation and Government Claims Board sets stringent standards for demonstrating innocence, although a recent state law has somewhat eased the requirements.

The report said some communities, including Alameda and Santa Clara counties and the cities of El Cerrito and Los Gatos, are overhauling police lineups and eyewitness identification practices to reduce errors, and San Francisco has made one recommended change, showing suspects and photos to witnesses one by one rather than in a group.

But the report also noted that a decade ago, the statewide Commission on the Fair Administration of Justice, whose members included police and prosecutors as well as defense lawyers, had issued numerous recommendations to reduce wrongful convictions. The proposals went nowhere in the Legislature, and few cities or counties have adopted them.

To Learn More:

Criminal Injustice: A Cost Analysis of Wrongful Convictions, Errors, and Failed Prosecutions in California’s Criminal Justice System (by Rebecca Silbert, John Hollway, and Darya Larizadeh; Chief Justice Earl Warren Institute on Law and Social Policy, University of California, Berkeley School of Law)

Kamala Harris Flips on Murder Case after Federal Judges Rip Prosecutorial Misconduct (by Ken Broder, AllGov California)

California Best at Exonerating Wrongly Convicted, to the Disappointment of Prop. 34 Foes (by Ken Broder, AllGov California)