A San Francisco judge ruled Tuesday that a man imprisoned for 18 years was wrongfully convicted in a double-murder case in which San Francisco authorities failed to tell the defense that they paid thousands of dollars to the star witness.

Caramad Conley, 40, has been locked up since 1992 - serving two life-without-parole terms in the 1989 double slayings on Third Street that prosecutors claimed were gang-motivated.

He may soon be free as a result of the ruling by San Francisco Superior Court Judge Marla Miller, who found that Conley was denied a fair trial and unconstitutionally convicted.

Miller found that police investigators knew that the prosecution's star witness, Clifford Polk, lied on the stand about whether he was being paid, but they did nothing to intervene.

Citing "voluminous evidence" that Polkwas lying when he claimed he was not in witness protection and therefore not receiving benefits, Miller went further, finding that the lead investigator in the case, Earl Sanders - who later became police chief - knew about the perjury. "I find that Sanders knew the testimony was false and did not correct it."

Sanders could not be reached for comment, and the prosecutor in the case, former San Francisco Assistant District Attorney Al Giannini, did not return calls about the ruling.

Previous Sanders case

Conley, currently held in Calipatria State Prison, is not the first defendant to have been wrongly convicted in a case involving Sanders.

His case bears strong similarities to court findings that led to the release of Antoine Goff and John Tennison in another botched murder case that resulted in a record civil settlement last year of $7.5 million for the defendants, who were both freed in 2003 after spending more than 10 years in prison.

In that case, the courts found that prosecutors and police had information that another person might have committed the crime but did not disclose it during the trial.

In the latest case, San Francisco prosecutors said they will review the findings and decide whether to appeal the ruling in favor of the defendant. They declined further comment.

Both cases involved the same investigators, the late Napoleon Hendrix and Sanders, who retired in 2003.

The cases also both involved allegations that courts found had merited overturning murder verdicts because investigators had withheld exculpatory evidence defense attorneys were constitutionally entitled to.

Key testimony

In the Conley case, prosecutors claimed he shot and killed two people - Roshawn Johnson and Charles Hughes - in a gang-related drive-by on April 8, 1989. They based their case largely on the testimony of a key witness, Polk, who was a police informant. Johnson and Hughes were gunned down on Third Street in a shooting that left 11 others injured.

Polk recounted in the 1994 trial that the defendant confessed to him. Polk admitted on the stand that he was a prior police informant who was previously under witness protection because of his testimony in another case. But, when asked on the stand if he was currently under witness protection, he denied it.

However, while researching San Francisco records in the Tennison-Goff murder conviction challenge, Tennison's attorneys stumbled onto the previously undisclosed witness protection payment records involving Polk in the Conley case.

Unmarked boxes

Other key documents were found under piles of debris in unmarked boxes at a police warehouse in Hunters Point, said Daniel Purcell, one of Conley's lawyers.

It turned out, Purcell said, that Sanders started paying Polk - an unemployed transient with a history of drug dealing - just three months before the Conley trial in September 1994. Purcell said Polk was getting weekly payments - and Sanders ultimately acknowledged those payments in testimony during a court-ordered deposition earlier this year in the case.

Sanders said he told the San Francisco prosecutor, Giannini, about the payments. Giannini testified, however, that he was never told of the payments.

In any event, Judge Miller found that the payments should have been disclosed to the defense.

Purcell said his client's constitutional rights were clearly violated.

"This was an easy case - it's a case where the police and prosecutors paid the essential prosecution witness thousands of dollars over a period of months and let him lie about it on the stand."

Purcell said that prosecutors tried to argue that the witness was right when he testified he was not under witness protection because he was not part of an officially sanctioned state program. He was, however, being protected or paid as part of San Francisco's own program.

"It didn't really pass the laugh test and the judge didn't give it any credit," he said.

Prosecutors now must decide whether to appeal the ruling or accept it and allow Conley's release. They can also seek a new trial.

Polk, however, died two years ago and all that's left is the same testimony he gave during the 1994 trial - in which the defense did not have the ability to ask about the payments.

"He's about as thoroughly impeached as can be," Purcell said.