FRESNO, Calif. — A federal court on Monday unsealed graphic excerpts of motel handyman Cary Stayner's confession to the 1999 murder of a Yosemite National Park naturalist after an appeals court refused to bar their release.

The graphic confession confirmed what had previously been reported based on unidentified law enforcement sources and offered the most detailed glimpse about what Stayner thought as he murdered Joie Armstrong and about her desperate fight for her life.

Stayner, 39, was sentenced in November to life without parole for Armstrong's July 21, 1999, beheading. He also faces trial in the murder of three tourists but has pleaded not guilty.

His attorney said Monday she feared the documents' release will make it tougher for Stayner to get a fair trial.

Prosecutors submitted the confession excerpts to support their bid to execute Stayner for killing Armstrong in a "heinous, cruel and depraved manner."

The documents were impounded while Stayner faced federal trial but were ordered released after he pleaded guilty to murder and was sentenced to life without parole, thus avoiding a possible death sentence.

The 9th U.S. Circuit Court of Appeals rejected a defense motion to postpone the release of the documents, which were sought by news organizations, who argued that the public had a right to know why the U.S. government wanted to put Stayner to death, and why defense lawyers opposed it.

The confession excerpt provides a further look at what drove Stayner to kill as he saw Armstrong outside her remote cabin, loading her car for a trip to San Francisco. Stayner, 39, said he knew what he did was wrong and acknowledged it was a cold-blooded act but said he lost control.

Initially, he didn't intend to kill. But as he watched the nature guide walking back and forth to her car and watering her plants, it occurred to him that she was alone and the thought of killing entered his mind.

He began talking to Armstrong and pulled a gun, forcing her into her house and saying he was going to rob her. He bound her mouth and hands with duct tape and forced her into his truck with the intent of raping and murdering her, prosecutors said in a summary of the confession.

The excerpts describe how, gagged and bound with duct tape, Armstrong made an effort to escape her killer, diving headfirst out the window of his moving truck and running for her life.

Stayner quickly tackled her, dragged her deeper into the woods of Yosemite and, as she vigorously fought back, slit her throat. He said Armstrong tried to pin her chin to her chest to block the knife.

He dragged her farther into the forest, down a hill and put his foot on her head and began cutting again.

"After the second cutting she was still struggling slightly, and I grabbed her leg and started dragging her, and just a few seconds later she went totally limp," he said.

He tried to cover his tracks but said it was difficult to hide the trail of blood with pine needles and dirt. He went back to his truck and then decided he would return to the creek where he had dragged her body and cut her head off. He said he tried to hide the head in some reeds and briefly considered keeping it.

"So you felt pretty good that you were able to pull this off?" one of the interrogators asked.

"I didn't feel good about it," he replied. "I say it's like matter of factly I was doing this, you know. It's like I'm a split personality."

Defense lawyer Marcia A. Morrissey said Stayner will have a harder time in his impending state trial for the killings of three Yosemite sightseers. The interrogation was never ruled admissible in court, and excerpts from it could sway potential jurors who may never hear that evidence at trial.

Stayner pleaded not guilty Wednesday to the February 1999 killing of three guests of a rustic motel where he worked outside the park's western gate.

The burnt bodies of Carole Sund, 42, and Silvina Pelosso, 16, were found in the trunk of a rental car a month after they disappeared. A week later, the body of Sund's daughter, Juli, 15, was found near a reservoir miles away.

The killings remained unsolved until Stayner's tire tracks linked him to Armstrong's slaying and he confessed to all four killings, investigators said.

Editors at news organizations that sought the records said Monday's decision was a victory for the public's right to know the government's reasoning for planning to seek capital punishment.

"The citizens have a right to know how the law gets enforced," said David Yarnold, San Jose Mercury News executive editor.

The Mercury News, owned by Knight Ridder Inc., sought the records along with the Hearst Corp., which owns the San Francisco Chronicle; The Associated Press and The McClatchy Co., publisher of the Sacramento Bee, the Fresno Bee and the Modesto Bee.