A Charles County Circuit Court judge on Thursday sentenced a Waldorf youth to 20 years in prison for stabbing a jogger who was on his morning run.

Circuit Court Judge Richard J. Clark suspended 10 years of the sentence he imposed on Alexander Scott Teacher, 16, one of three people convicted in the Jan. 23 attack.

Two others who took part in the attack have entered guilty pleas without going through trials. On Friday, a juvenile court hearing began for the fourth person charged in the attack.

Teacher was convicted in June of assault and conspiracy for stabbing Ronald Oliver, 60, three times as Oliver jogged before dawn along Billingsley Road in western Charles County.

According to testimony at Teacher's trial, he had spent the night before the assault drinking with other youths and believed the attack would gain him membership in a nationally known gang. Charles County police say no branch of the gang is active in the county.

Teacher spoke briefly at his sentencing, saying he was sorry for the attack.

His statement came after Christine Oliver, the victim's wife, testified that her husband remained traumatized six months after the assault. Ronald Oliver declined to attend Thursday's sentencing.

"It's been very difficult for my husband," Christine Oliver said. "He's not dealing with this well at all."

She said Oliver, who had run four miles every day, no longer jogs, in part because of persistent, unexplained pain in his feet.

Assistant State's Attorney Michael C. DiLorenzo said Teacher's crime had "a chilling effect" on the community, creating the impression that "you are not safe to walk or jog."

Defense attorney Franklin B. Olmsted said Teacher, who was 15 years old at the time of the attack, was manipulated by the others involved.

According to testimony, a group of youths spent a night driving around western Charles County in a pickup truck and drinking. Three jumped from the truck's bed after spotting Oliver and punched him, knocking him to the ground, then stabbed and kicked him.

"This wasn't Alex's idea," Olmsted said. "He was being used by more sophisticated ones that got him drunk . . . and induced him to do this evil thing."

Clark decided during the trial that alcohol use did not absolve Teacher and said Thursday that the youth bears responsibility for his actions.

"I don't think a good person could commit a crime like this," the judge said.

He handed Teacher 20 years for each conviction, with sentences to run concurrently, and suspended all but 10 years.

Randy Paul Rogers Jr., 17, who authorities allege drove the pickup truck and waited while Oliver was kicked and stabbed, pleaded guilty to conspiracy on July 1. Under a plea agreement, Rogers is to receive no more than 10 years in prison when he is sentenced Sept. 2 by Circuit Court Judge Robert C. Nalley.

A 13-year-old admitted involvement in the attack this spring and is now in the custody of juvenile authorities. The Washington Post does not normally identify subjects of juvenile proceedings.