A man jailed for four years awaiting a death penalty trial has taken the unusual step of pleading guilty to capital murder in a case that shocked Las Vegas for its brutality: the rape, torture, killing and mutilation of a 15-year-old girl on her way home from school.

Javier Righetti was 19 when killed Arbor View High School sophomore Alyssa Otremba. She disappeared Sept. 2, 2011, after texting her mom that she was walking home from school. Her burned body was found in a vacant lot the next day.

Now 23, Righetti pleaded guilty Feb. 11 to all charges against him — including kidnapping, robbing and trying to rape another teenage girl in Las Vegas in March 2011.

He got no promise that he won't be put to death.

It's "extraordinarily unusual" to plead guilty before a capital murder trial with no deal from prosecutors to seek life in prison without parole instead of the death penalty, Righetti's court-appointed defense attorney said Tuesday.

"He didn't deny that he did it," Christy Craig said. "He was aware of what this meant. He just didn't want to put anybody, including the family of the victim and his family, through a long trial."

A Clark County District Court jury is due to begin March 15 to consider whether Righetti should be executed.

Righetti last week told Judge Michelle Leavitt he kidnapped, sexually assaulted and stabbed Otremba dozens of times before burning her corpse in northwest Las Vegas.

A prosecutor told a judge in October 2011 that Righetti provided a detailed confession following his arrest.

"It made him feel powerful," prosecutor Christopher Lalli said at the time. "He said he did it because it made him seem more like a gangster or a thug."

Righetti also was suspected of sexually assaulting a female cousin in Mazatlan, Mexico, Lalli said at the time, and served time in a Nevada Youth Training Center in Elko for a sexually motivated kidnapping.

Craig said Righetti knew his plea and penalty trial would get attention, and he wanted to retain his ability to appeal the jury decision.

"There's very little he has control over," the defense attorney said. "This will get intense scrutiny as it winds through appeals — even more so because he's pleading guilty to all counts."

Kent Morgan, a veteran Utah attorney who won death penalty cases as a prosecutor in Salt Lake City, interpreted Righetti's plea as a declaration of his "sense of his own importance as criminal."

"He likes being the center of attention," Morgan said. "He's not avoiding trial. All the material that would come out will come out in the penalty phase. He's saying, 'I'm in charge here, nobody else.'"

Prosecutors Giancarlo Pesci and Michelle Fleck held firm without an offer of a lesser sentence. They said Righetti's attorneys will be able to argue that he's remorseful and is taking responsibility for his crimes.

"This spares the jury of hearing the argument that he didn't do it," Pesci said.

Some compared Righetti's decision with the 2005 guilty plea by Beau Maestas, a Utah man, in a January 2003 carving knife attack that killed a 3-year-old girl and paralyzed her 10-year-old sister in Mesquite, about 80 miles northeast of Las Vegas on the Arizona border. One jury deadlocked before another jury sentenced Maestas to death.

Maestas, now 32, is one of about 80 people on death row in Nevada, where the last execution was in 2006. He has an appeal pending before the Nevada Supreme Court.

Maestas' sister, Monique Maestas, pleaded guilty to the same charges as her brother, but wasn't eligible for the death penalty because she was 16 at the time of the attack. She's now 29, and is serving 47 years to life in prison.