WALLA WALLA, Wash. - The prosecutor was in the middle of his opening statement, describing in vivid and disturbing detail the murders of Homer and Vada Smithson, who had just celebrated their 70th wedding anniversary.

The defendant, Donald Lambert, 16, doodled as he listened. Then, court records show, he passed a note to his lawyer. It said he wanted to plead guilty.

Mr. Lambert entered his plea 13 minutes later, after a brief conversation with his lawyer, Guillermo Romero. The plea required Mr. Lambert to spend the rest of his life in prison. Mr. Lambert said Mr. Romero, who has since been disbarred, offered him no guidance.

"He didn't go into, like I know now, that it was my whole life," Mr. Lambert said in an interview at the Washington State Penitentiary here. "None of my family was in the courtroom. I was on my own."

There is little question of Mr. Lambert's guilt. But there are substantial ones about whether he and other juveniles facing life sentences are competent to make decisions with permanent consequences. Had Mr. Lambert rolled the dice and allowed the trial to proceed, he could have done no worse than what he agreed to in his plea.

In Washington as in other states, minors who sign a contract to buy a stereo or a bicycle are allowed to change their minds. They are, in the words of the State Supreme Court, "incompetent to contract away their rights."

But minors are allowed to enter binding plea agreements that call for life without the possibility of parole.

"He's got a right to plead guilty," said John Knodell, who prosecuted Mr. Lambert. "We trust kids that age to get an abortion."

Mr. Lambert, now 23, is an imposing young man, six feet of blocky muscle under a white T-shirt and blue jeans. He is covered in ugly prison tattoos, created with the motors from cassette decks. The tattoos climb up his neck, onto the back of his big square head and over an eyebrow. They compete for attention with a scar on his forehead. The combined effect is menacing.

At the prison interview here, Mr. Lambert's new lawyers instructed him not to answer questions about the killings.

But according to court records, early in the morning on May 21, 1997, Mr. Lambert, then 15, and Adam Betancourt, 16, burst into the bedroom of Mr. and Mrs. Smithson, both in their late 80's, in Quincy, Wash.

The youths shot Mr. Smithson many times, in the head, chest, legs and abdomen, and then went outside to reload. Mrs. Smithson made a desperate phone call to her son: "They're killing me!"

"The phone was right by a big kitchen window," recalled Al Smithson, the couple's son. The youths then shot her through the window. "They peppered her big time," Mr. Smithson said.

In 2003, a federal judge in Spokane threw out Mr. Lambert's guilty plea, calling his lawyer's conduct "unprofessional," "egregious" and "a dereliction of duty."

"Mr. Lambert had everything to lose by entering the guilty plea," wrote Judge W. Fremming Nielsen, who was appointed by the first President Bush. The decision to plead guilty to aggravated first-degree murder "was the most important decision of his life, and he was forced to make it without essential information."

There was evidence, Judge Nielsen wrote, suggesting that Mr. Lambert incorrectly thought he was facing the death penalty and that the sentence he pleaded to would allow him to be paroled after 20 years.

Mr. Romero, the defense lawyer, was disbarred last year for conduct unrelated to Mr. Lambert's plea. In an interview, Mr. Romero said his former client pleaded guilty with full knowledge of the consequences. Mr. Romero said he was unsurprised that Mr. Lambert now claims to have been confused.

"I would lie on my mother's grave," Mr. Romero said, "if I thought it would save me from life in prison."

Judge Nielsen, in his 2003 decision, ordered prosecutors to try Mr. Lambert or release him. But the United States Court of Appeals for the Ninth Circuit, in San Francisco, reversed that ruling last year, saying Mr. Lambert had known what he was doing when he pleaded guilty.

Copyright 2005 The New York Times Company. Reprinted from The New York Times, National, of Monday, October 3, 2005.