A 20-year-old man was sentenced yesterday to 30 years in prison for participating in what the judge called the torture killing of a Gaithersburg youth in a remote Montgomery County park on Labor Day 1998.

Joseph Morrongiello, of the 16000 block of Horn Point Drive in Gaithersburg, hung his head but otherwise showed no emotion as Montgomery County Circuit Court Judge Nelson W. Rupp Jr. told him that the slaying was "a parent's worst nightmare. It's our community's worst nightmare."

Morrongiello's sentencing was the last of three in the stabbing death of Kirill Varnovatyy, 15, a Northwest High School sophomore and the only child of Ukrainian immigrants who say they brought their son to the United States for a safer, better life.

Varnovatyy's badly decomposed body was discovered after it emerged from a storm drain in Quince Orchard Valley Park two weeks after he disappeared Sept. 7, 1998. He had been beaten on the head, stabbed 28 times and almost decapitated by a slice to his throat.

Assistant Montgomery State's Attorney Blair Berman said Morrongiello and two other teenagers lured Varnovatyy into the park with promises of beer but intentions of beating him that eventually turned to murder.

After hitting Varnovatyy in the head with a rock, one of his attackers, Aaron Goldfarb, then 15, announced, "I have to kill him," and held Varnovatyy at knifepoint with a switchblade, Berman said.

Morrongiello and another youth, Zachary Marshall, then 16, walked off to smoke cigarettes but returned to see what was taking Goldfarb so long, Berman said. The group then marched Varnovatyy at knifepoint for more than 45 minutes to a secluded area, while the victim pleaded for his life, Berman said.

While Goldfarb stabbed and the youth screamed out in pain, Berman said, Morrongiello reached in to hold the victim's arms back.

Varnovatyy's mother, Rada Varnovatyy, cried as she sat in a front-row seat in the courtroom. Upon hearing the repeated details of her son's murder, she covered her ears with her hands.

Goldfarb was sentenced in September to life in prison after pleading guilty to first-degree murder. Marshall, who like Morrongiello pleaded guilty to second-degree murder, was sentenced in November to 30 years in prison.

Morrongiello, who was working at Kmart and attending Montgomery College at the time of the murder, told the judge: "I'm really sorry for what happened. I apologize to you. I apologize to the family. I'm really sorry. That's all."

Defense attorney Gary L. Crawford said his client had attention deficit disorder and a diagnosed psychological disorder but had never been in trouble before and was "extremely remorseful" over Varnovatyy's slaying.

"My client was simply overwhelmed as the situation changed from an assault--however cowardly that was--into a murder," Crawford said.