The second of two Prince George's County men convicted of hurling rocks at Capital Beltway motorists was sentenced yesterday to 39 years in prison for an attack that injured more than two dozen people, including a teenage girl who suffered permanent brain damage.

Donnell R. Petite, 18, convicted last month of 42 criminal charges, told Circuit Court Judge William D. Missouri: "I'm sorry for what I've done. I didn't mean to hurt anyone."

The judge then asked him, "What did you anticipate would happen when you threw the rocks at the cars, sir?"

Petite, in a low voice, said, "I didn't anticipate anything."

Authorities said Petite and two other young men, all from Oxon Hill, were intoxicated last May 27 when they hurled five- to 15-pound landscaping stones at Beltway traffic near the Livingstone Road underpass.

The most seriously injured victim, Destiny Morris, 16, of Hagerstown, Md., suffered a skull fracture and was comatose for six weeks. She is not expected ever to function above the mental level of a 9-year-old.

Petite's attorney, Maureen Lamasney, told Missouri the attack was "truly a senseless crime," but described her client as "a very polite, respectful young man" who has "expressed extreme remorse about this."

She said Petite has "wrestled with, and, for all intents and purposes, overcome a drug problem of his own." Calling him "a young man with great potential," she said, "basically what we're asking for is mercy."

But the judge replied, "I must think about the victims."

"At the start of this new year, this {sentencing} gives me no joy," said Missouri, who presided at Petite's non-jury trial in Upper Marlboro and found him guilty Dec. 11 of eight felonies and 34 misdemeanors.

"But because of what you have done," he told Petite, "there are people out there who have lost their joy forever."

Missouri also presided at the non-jury trial of the first defendant in the case, John L. Burgess, 18. He sentenced Burgess to 38 years in prison after convicting him Nov. 1 of eight felonies and 30 misdemeanors. The third defendant, Maurice E. Ford, 19, is scheduled to go on trial Feb. 25.

Petite, like Burgess, was convicted of one count of assault with intent to maim, seven counts of assault with intent to disable and numerous counts of assault and battery and destruction of property.

Under Maryland law, they will become eligible for parole hearings after serving about 10 years.

Besides Morris, nearly 30 people in 24 vehicles were injured in the early-morning attack, including a Landover man who lost his right eye and a Manassas woman who lost the hearing in her right ear.

Prosecutor John Smathers recommended 50 years for Petite, but said he was pleased. "This was the last thing these guys expected when they were throwing rocks through windshields, that they'd get almost 40 years in prison," Smathers said. "I'm sure it shocked them, and I hope it sends a signal to others."