-- After more than a quarter of a century proclaiming their innocence, four former members of the Symbionese Liberation Army pleaded guilty to murder today in the shotgun slaying of a bank customer during a botched holdup in 1975.

Among the four aging radicals who admitted their part in the killing was Sara Jane Olson, 55, who lived quietly under an assumed name as a cookie-baking physician's wife in Minnesota for almost 25 years before her arrest in 1999 on other SLA-related charges.

Olson is serving a 14-year sentence after admitting guilt last year in the attempted murder of Los Angeles police officers, whom she tried to assassinate with a bomb that failed to explode.

Today, Olson and three former SLA comrades pleaded guilty to second-degree murder in a deal with prosecutors in Sacramento to avoid a possible sentence of life in prison. The four will be sentenced to prison terms of six to eight years.

The other three former SLA members are William Harris, 57, who went by the name "General Teko" in the SLA and later lived in the Bay Area and worked as a private investigator; his ex-wife, Emily Montague, 55, known as "Yolanda," who became a computer network designer in the Los Angeles area; and Michael Bortin, 57, a craftsman who lived outside Portland, Ore.

Still wanted in connection with the murder is James Kilgore, 55, another former SLA member who has been on the run since 1975.

All five belonged to the 1970s revolutionary cell that kidnapped newspaper heiress Patricia Hearst, who was to be the government's chief witness at the trial that had been set for next year. The SLA began as a theater group and morphed into a gang that wanted to bring down the Establishment.

After she was kidnapped, Hearst participated in a series of SLA bank robberies, including the one at Crocker National Bank in suburban Sacramento. There Harris is believed to have shot to death Myrna Opsahl, a nurse and mother of four who had come into the bank to deposit her church's collection plate donations. Opsahl, 42, died at the hospital where her husband was a physician.

Hearst wrote in her memoir that Harris had admitted shooting Opsahl, but said, "It doesn't really matter." Hearst also remembers Harris calling Opsahl "a bourgeois pig."

Opsahl's son, Jon Opsahl, has pushed police and prosecutors for years to pursue charges against the SLA in the bank slaying. But only recently could FBI tests prove that the lead pellets fired from the shotgun into his mother matched a pellet found at an SLA hideout in San Francisco years ago.

Jon Opsahl said today that he is satisfied with the plea bargain, and pleased his mother's murderers are finally held accountable.

"The SLA has been proven wrong," he said. "My mother's death did matter."

The defendants agreed to give up rights to profit from their stories.

Stuart Hanlon, the attorney for Emily Montague, said that his client had long wanted to confess to the murder. "I don't think people know what it's like to spend everyday knowing you're responsible for killing somebody."

Special correspondent Kimberly Edds contributed to this report.