A Montgomery County teenager was sentenced yesterday to life in prison for the stabbing death of a 15-year-old friend whom he lured to a remote county park last September, a crime that the judge called "extraordinarily cruel."

Aaron Goldfarb, 16, sobbed an apology to the parents of Kirill Varnovatyy, the Northwest High School sophomore whom he pleaded guilty to stabbing repeatedly on Labor Day last year.

The body of Varnovatyy, the only child of Ukrainian immigrants, was found in a heavily wooded park two weeks after he disappeared. He had 28 stab wounds, cuts on his hands and a deep slit to his throat that almost decapitated him, prosecutors said.

"I know why I need to be punished, probably more than anyone in this courtroom today," Goldfarb told Montgomery Circuit Court Judge Nelson W. Rupp Jr. as he gasped for breath between sobs. "I hate the person I've become. I'm sorry to the Varnovatyy family. I'm hurting, too. I'd give everything I have to take back what I did."

Rupp said he found Goldfarb's remorse genuine and appreciated a psychiatrist's opinion that the youth suffers from depression, post-traumatic stress disorder and severe rage as the victim of sexual abuse, allegedly by his father.

However, the judge said, "the torture and terror Mr. Varnovatyy experienced is unimaginable. . . . There is absolutely no reasonable assurance it would not happen again."

He told Goldfarb, "You will spend the rest of your life in prison."

Maryland criminals sentenced to life in prison can become eligible for parole after serving 15 years, with the governor's approval.

Goldfarb pleaded guilty to first-degree murder after prosecutors agreed not to seek life without parole, Deputy State's Attorney Katherine Winfree said.

Prosecutors said Goldfarb and two other youths, Zachary Marshall and Joseph Morrongiello, told Varnovatyy that they were going to the park to drink beer. But after walking into the woods, Winfree said, Goldfarb struck Varnovatyy in the head with a rock and the trio punched and kicked him.

Leading Varnovatyy at knifepoint to a more secluded area, Goldfarb ordered him to sit, then stabbed him as Varnovatyy begged him to stop, prosecutors said.

Marshall, 16, and Morrongiello, 20, both pleaded guilty to second-degree murder and are scheduled to be sentenced in November.

Goldfarb's attorney, Harry Trainor, had asked the judge to consider that Goldfarb suffered years of sexual abuse that led him to abuse heroin and alcohol.

The judge rejected his request that Goldfarb be recommended for a special program that provides psychiatric treatment to young offenders sentenced to the adult prison system.

During an emotional two-hour hearing, two women wept over sons they said they had tried to protect. One mother told of the loss of her dead son, and the other pleaded for mercy for her own.

"It's very easy to walk in here and label my son a monster," said Cheryl Etchison, Goldfarb's mother. "He's not a monster. He's the boy next door. The real monster here is drug abuse, alcohol abuse, peer pressure and sexual abuse--none of which he asked for."

Gesturing toward Varnovatyy's parents in the front row, Etchison tearfully apologized and said both their sons had been "destroyed."

"We don't live in their world," Etchison said, as Goldfarb cried at the defense table. "We live in our world. What they do when we're not with them, we have to trust.

"We live in a middle-class family in Montgomery County," she added. "How could this happen? If it could happen in my family and in my community, it could happen anywhere."

Goldfarb's father, Dovid Goldfarb, is on unpaid leave from his job as a D.C. police sergeant and is scheduled to stand trial in November on charges of sexually abusing his son and daughter.

Rada Varnovatyy told the judge that she and her husband, Yakov, emigrated from Ukraine when their son was 9 years old because they were Jewish and they thought he would be safer in the United States.

"It was to protect him," she said, crying. "But it was wrong."

Glancing toward Goldfarb, she sobbed, "He's crying now, but probably my son was crying and asking him not to kill him."