Olson wasn't brought to trial for almost a quarter of a century

Sarah Jane Olson was freed on Monday after seven years in jail for attempted bombings and second-degree murder during a campaign in 1975.

But officials found an "administrative error", and realised she still had one more year to serve before being freed.

Olson's lawyer said the California prison authorities were "bowing to political pressure".

Olson, 61, will not now be eligible for parole until March 2009.

Formerly known as Kathleen Soliah, she was a member of the militant Symbionese Liberation Army.

The group became famous for kidnapping newspaper heiress Patty Hearst in 1974.

Olson then went on the run for almost a quarter of a century, marrying and living undetected in Minnesota.

Release criticised

After a tip-off, she was arrested in 1999 and in 2001 she was found guilty of attempted bombings. In 2003 she also pleaded guilty to second-degree murder over the death of bank customer in a 1975 robbery near Sacramento.

In all, she was sentenced to 14 years in prison.

Her early release brought protests from a Los Angeles police officers union.

On Friday, she was detained at Los Angeles airport, as she was about to fly to Minnesota. She had informed her parole officer about the journey.

She will now be returned to the same prison from which she was released earlier in the week.

Officials said that the error in her release date was because of a failure to factor the second sentence into her parole calculations.

But Olson's lawyer said that was "ridiculous".

"We received an order from the state parole board more than a month ago informing us that she would be released on 17 March," said Shawn Chapman Holley.

"The idea that suddenly they discovered an error is untrue," she added. "As far as we're concerned they're bowing to political pressure and they are wrong."

The Symbionese Liberation Army formed in Berkeley, California in the 1970s, committed to fighting against what it said was an oppressive governmental regime.

The group carried out a series of bombings, murders and robberies before most of its members were killed in a dramatic fire in 1974 after a gun battle with Los Angeles police.