LOS ANGELES — The judge in Sara Jane Olson's upcoming bombing trial ruled Wednesday that her defense can challenge the legality of 1975 police searches of properties linked to the Symbionese Liberation Army.

Judge Larry Fidler's decision means the prosecution must put FBI agents and police officers on the stand next week to justify searches of apartments, a car and a mailbox allegedly used by the SLA, the violent radical group to which Olson is accused of belonging. Those searches yielded evidence, including guns, bombs and Olson's fingerprints, prosecutors hope will prove she was in on a plan to blow up police cars in 1975.

"I'm very happy. I consider it a victory today," said Olson after court. Dressed in a blue and green velvet pants suit and surrounded by her husband and three daughters, the former radical fugitive added, "It does give us an opportunity to start chipping away the main prosecution, which is to take me with a conspiracy charge."

The 54-year-old faces life in prison if convicted of murder conspiracy. Prosecutors allege that in 1975, Olson, then known as Kathleen Soliah, planted pipe bombs under a pair of black-and-white patrol cars in Los Angeles. The bombs, which prosecutors say were intended as payback for the deaths of six SLA soldiers in a police shootout, never detonated and no one was injured.

A month later, with police closing in on the group, Olson fled. She moved to Minnesota where she married a physician and built a new life as a civic-minded housewife and amateur actress. In 1999, after the television show America's Most Wanted aired a segment on her case, the FBI arrested her.

Patty Hearst, who became an SLA convert after her abduction, is expected to be the prosecution's star witness in the case, likely to get under way next month, but prosecutors need to bolster her testimony with other evidence, including that recovered during the 1975 searches.

Prosecutor Michael Latin argued that because Olson did not own the apartments, mailbox or car searched, she did not have proper standing to object to the searches. But Olson's lawyer Shawn Snider Chapman persuaded Fidler that the law governing the searches was the law of the time and in 1975, Olson would have been allowed to challenge the searches, ownership or not.

At the hearing scheduled for next Wednesday, police and FBI agents are expected to testify that they conducted some of the searches without warrants because they feared immediate danger from the SLA. District attorney's office spokeswoman Sandi Gibbons dismissed Olson's talk of a victory, saying, "I think this evidence will come in at trial."

Fidler postponed further pretrial hearings until Thursday because Olson's second defense lawyer, J. Tony Serra, is still finishing another case in Modesto.

Among the issues to be discussed is a defense motion that the case be dismissed because the prosecution failed to provide a diary from SLA associate Wendy Yoshimura, who was arrested with Hearst in 1975 and later convicted of weapons charges. According to the defense, Yoshimura provided an alibi in the diary, writing that Olson was in Northern California on the day of the attempted Los Angeles bombings.

Gibbons said Wednesday that the diary was destroyed in the 1980s along with other evidence from Yoshimura's trial in a standard procedure for older case files.

"We can't turn over what we don't have," said Gibbons, adding that the defense could call Yoshimura, now an artist living in Berkeley, as a witness.