Denison first tried to log into the ISO's computer system, but was unsuccessful because his computer privileges had been suspended, investigators said. Denison broke a glass cover that protected an emergency shut-off button, meant for use in case of fire or other calamity, according to the release.

Denison allegedly went home after shutting off the power to the computers, and told a friend the next morning that he had pressed the emergency button and had tried to "shut off the power grid," according to prosecutors.

The ISO manages high-voltage lines owned by Pacific Gas and Electric Co., Southern California Edison and San Diego Gas & Electric Co. The April 15 outage disrupted CalISO communications for about two hours, leaving the grid vulnerable to electricity shortages. The ISO used back-up systems to reconnect to the energy market.

Denison is scheduled to be sentenced by U.S. District Judge Garland E. Burrell Jr. at 9 a.m. on Feb. 29. The maximum penalty for attempting to damage an energy facility is five years imprisonment, a $250,000 fine and a three-year term of supervised release. Denison originally had also been charged with making a bomb threat.

The case was investigated by the Federal Bureau of Investigations's Joint Terrorism Task Force, composed of federal, state and local law enforcement agencies.

Kevin James, 31, and Levar Haley Washington, 28, entered their pleas in separate appearances before U.S. District Court Judge Cormac J. Carney. Washington also pleaded guilty to using a firearm to further the conspiracy. Prosecutors said he used a shotgun to rob a Torrance gas station on July 4, 2005.

James faces up to 20 years in prison when he is sentenced March 31. Washington faces up to 20 years in prison on the conspiracy charge and five years to life for the firearms offense when he is sentenced April 28.

Authorities say James, Washington and two others were part of a California prison gang cell of radical Muslims that planned the attacks in the Los Angeles area.

"Homegrown terrorism remains a grave concern to the security of our country, and this cell was closer to going operational at the time than anyone since 9/11," Los Angeles Deputy Police Chief Michael Downing told reporters at a news conference after the two men entered their pleas.

Police uncovered the plot in July 2005 while investigating a string of gas station robberies that authorities say were committed to finance the attacks. Torrance Police Chief John Neu told reporters at the news conference that authorities linked about 10 holdups to the plot.

The plotters were within weeks of being able to carry out an attack, officials said, when they were discovered about two months before the Jewish holiday Yom Kippur.

Washington and James, who arrived in court in chains and prison jumpsuits, said little during their separate hearings. Both men wore goatees and Washington's face was covered in tattoos.

Washington's attorney, Ellen Barry, said outside court that her client decided it was "in his best interests" to plead guilty. James' attorney, Robert Carlin, declined to comment.

Also indicted in the case were Gregory Vernon Patterson and Hammad Riaz Samana. All but Samana, a Pakistani national, are American-born Muslim converts.

Patterson and Samana are charged with conspiracy to levy war against the U.S. government through terrorism, conspiracy to possess and discharge firearms in a violent crime, conspiracy to kill members of the U.S. government uniformed services and conspiracy to kill foreign officials. Patterson is also charged with a robbery count and using a firearm in a violent crime.

U.S. Attorney Thomas O'Brien said Samana has been declared mentally unfit to stand trial and is undergoing psychiatric care at a federal prison facility. Patterson is expected to plead guilty to a terrorism conspiracy charge on Monday.

Prosecutors say the plot was orchestrated by Washington, Patterson and Samana at the behest of James, a California State Prison, Sacramento, inmate who founded the radical group Jamiyyat Ul-Islam Is-Saheeh, or JIS.

Court of Criminal Appeals Presiding Judge Sharon Keller contends that while she ordered the clerk's office closed promptly at 5 p.m., state law clearly gave attorneys for death row inmate Michael Wayne Richard the power to contact judges on the court directly.

In papers filed in U.S. district court in Austin, Keller said Richard's lawyers made no attempt to contact any judges on the court, even though three were available Sept. 25, the date of Richard's execution in 1986 rape and murder of Marguerite Dixon, a Houston-area mother of seven. Keller said the clerk's office was closed but the court's building remained open.

Richard's lawyers were in Houston. The court is in Austin.

Keller has garnered national attention for refusing to extend the court's closing time prior to Richard's execution, despite calls from Richard's attorneys alerting her office they were experiencing computer problems and begging for extra time. But in a motion, Keller said Texas law "provides a clear and unambiguous avenue for litigants to file documents with the (Court of Criminal Appeals) directly through any of its judges, so Richard did not need the CCA clerk's office to stay open after hours to file his motion."

This is the first time Keller has claimed Richard's lawyers could have directly gone to other judges on the court. She previously has tried to shift blame to Richard's lawyers by saying they had all day to file.

Jim Harrington, director of the Texas Civil Rights Project, called Keller's argument "shameless."

"Everyone knows that the key is the clerk's office," said Harrington, whose office is representing Richard's daughter, Doreen Anderson, as well as other attorneys who have filed complaints against Keller for her handling of the appeal.

"The clerks are the ones who intercept the calls, who say 'it's shut down,' " Harrington said. "The rules of procedure in the law are supposed to serve justice and here you have a case where a guy's life is at stake. It's literally a matter of life or death and to fall back on some off-the-wall assertion, 'go find a judge and file it that way' is absurd. It makes a farce of the law."

American Tower Corp. said Thursday that it will pay $14 million to settle a consolidated securities class action filed against the company in May 2006 that concerns its historical stock option granting practices and related accounting.

The broadcast and communications tower operator said that under the settlement, claims against the company will dismissed.

American Tower said it will continue to communicate with its insurers about the insurers' contribution to the settlement.

American Tower expects to report an income statement charge for the amount of the settlement, plus certain related legal fees and expenses.

The Justice Department says it needs time and the freedom to probe the destruction of hundreds of hours of recordings of two suspected terrorists. After Attorney General Michael Mukasey refused congressional demands for information Friday, the Justice Department filed late-night court documents urging a federal judge not to begin his own inquiry.

The administration argued it was not obligated to preserve the videotapes and told U.S. District Judge Henry H. Kennedy that demanding information about them "could potentially complicate the ongoing efforts to arrive at a full factual understanding of the matter."

The documents represent the first time the government has addressed the issue in court. In the papers, acting Assistant Attorney General Jeffrey S. Bucholtz said Kennedy lacked jurisdiction and he expressed concern that the judge might order CIA officials to testify.

Congressional inquiries and criminal investigations frequently overlap and it is not uncommon for the Justice Department to ask lawmakers to ease off. The request for the court to stand down is more unusual. Judges take seriously even the suggestion that evidence was destroyed, but they also are reluctant to wade into political debates.

Legal experts say it will be up to Mukasey, a former judge who only recently took over as the nation's chief law enforcer, to reassure Congress and the courts during his first high-profile test.

"We're going to find out if the trust Congress put in Attorney General Mukasey was well placed," said Pepperdine Law professor Douglas W. Kmiec, who served in the Justice Department during the Reagan administration. "It's hard to know on the surface whether this is obstruction or an advancement of a legitimate inquiry."

Kennedy ordered the administration in June 2005 to safeguard "all evidence and information regarding the torture, mistreatment, and abuse of detainees now at the United States Naval Base at Guantanamo Bay."

Five months later, the CIA destroyed the interrogation videos, which involved suspected terrorists Abu Zubaydah and Abd al-Rahim al-Nashiri

Bucholtz argued that the tapes were not covered by Kennedy's court order because Zubaydah and al-Nashiri were not at the Guantanamo military prison in Cuba. The men were being held overseas in a network of secret CIA prisons. By the time President Bush acknowledged the existence of those prisons and the prisoners were transferred to Guantanamo, the tapes had been destroyed.

Lawmakers had reacted angrily to Mukasey's refusal Friday to give Congress details of the administration's investigation. He explained that doing so could raise questions about whether the inquiry was vulnerable to political pressure and said his department generally does not release information on pending cases.

"It's clear that there's more to this story than we have been told, and it is unfortunate that we are being prevented from learning the facts. The executive branch can't be trusted to oversee itself," according to a statement by the leaders of the House Intelligence Committee, Reps. Silvestre Reyes, D-Texas, and Pete Hoekstra, R-Mich.

They said "parallel investigations occur all of the time, and there is no basis upon which the attorney general can stand in the way of our work." Mukasey's decision, lawmakers said, blocks congressional oversight of his department.

David Remes, a lawyer who represents a Yemeni national and other detainees, has called for a court hearing. He says the government was required to keep the tapes and he wants to be sure other evidence is not being destroyed.

Even if Kennedy agrees that the government did not violate his order, he still could schedule a hearing. He could raise questions about obstruction or spoliation, a legal term for the destruction of evidence in "pending or reasonably foreseeable litigation."

Those are serious matters, but Kennedy does not necessarily have to hold a hearing right away, said K. Lee Blalack, a Washington defense lawyer and former counsel to a Senate investigative committee.

"If the department takes six months on this and reports back, nothing prevents the judge from taking up the issue then," Blalack said.

Kmiec said much will depend on how much confidence Kennedy has in the Justice Department. The judge also might order a private hearing to protect national security, Kmiec said.

Zubaydah was the first high-value detainee taken by the CIA in 2002. He told his interrogators about alleged Sept. 11 accomplice Ramzi Binalshibh, and the two men's confessions also led to the capture of Khalid Sheikh Mohammed, who the U.S. government said was the mastermind behind the terrorist attacks.

Al-Nashiri is the alleged coordinator of the 2000 suicide attack on the USS Cole in Yemen, which killed 17 sailors. Like Zubaydah, he is now at Guantanamo.

After 10 days of deliberations, the jury was unable to reach a verdict on the manslaughter charges against Alexander Pring-Wilson, 29, who was being tried for a second time.

Pring-Wilson said he acted in self-defense after he was attacked by 18-year-old Michael Colono and his cousin, Samuel Rodriguez, outside a Cambridge pizza parlor as he walked home from a bar on April 12, 2003.

Rodriguez testified that Pring-Wilson became enraged when Colono ridiculed him for stumbling home drunk.

The case attracted widespread media attention because of long-standing tensions between Ivy Leaguers and working-class Cambridge residents.

Pring-Wilson, the son of Colorado lawyers, was studying for his master's degree in Russian and Eurasian studies at Harvard. Colono, a high school dropout, had fathered a child at 15. He had earned his high-school equivalency diploma and was working as a cook at a Boston hotel when he was killed.

Pring-Wilson will remain free on bail. Prosecutors said they will put him on trial a third time.

"We will honor the memory of Michael Colono by continuing to fight for justice on behalf of him, his family, and the commonwealth," Middlesex District Attorney Gerry Leone said in a statement.

Pring-Wilson was convicted of manslaughter in 2004, but won a new trial eight months later when the state's highest court ruled in another case that juries should be allowed to consider a victim's violent history if it is relevant to a claim of self-defense.

During the second trial, jurors were given details about Colono's criminal record, including a 2001 episode in which he threw money in the face of a cashier at a pizza restaurant, then kicked in the front door and shattered the glass.

Pring-Wilson testified Colono and Rodriguez both pounded him relentlessly in the head, and he pulled out his folding knife because he was afraid they would kill him.

The fight between Pring-Wilson and Colono broke out as Pring-Wilson walked by a car Rodriguez and Colono were sitting in as they waited for a pizza order. Pring-Wilson said he approached the car because he heard someone call to him and thought they needed directions.

But Rodriguez said Pring-Wilson pulled open the car door and started the fight after Colono ridiculed him. Colono was stabbed five times in the chest and abdomen.

The prosecution focused on the lies Pring-Wilson acknowledged telling police during a 911 call he made seconds after the fight ended, and during police interviews the next morning. He initially said he had witnessed a young man being stabbed, but described himself as a bystander.

Pring-Wilson's attorney, E. Peter Parker, said the deadlock showed that at least some jurors rejected the prosecution's claim that Pring-Wilson was the aggressor.

"We are thrilled that a number of jurors at this trial saw the commonwealth's case for what it was, and found that Alex's conduct was a justified act of self-defense," Parker said.

Colono's brother, Marcos, and mother, Ada, did not immediately return a call seeking comment.