LEWISBURG — A central Pennsylvania teenager testified Tuesday against three of his friends in the Interstate 80 rock-throwing incident after reaching a plea deal with prosecutors in Union County.

Keefer McGee, 17, waived his preliminary hearing and will plead guilty to felony two aggravated assault in connection with the July incident in which prosecutors say he and three friends went on a troublemaking spree that ended in nearly killing an Ohio woman. As part of that deal, McGee will face time in a county prison.

Dylan Lahr, 17, and Tyler Porter, 17, also waived their preliminary hearings Tuesday but did not testify.

Brett Lahr, 18, proceeded with his preliminary hearing, and District Judge Jeffrey Mensch ruled that enough evidence existed to move forward with charges against him.

Each defendant is out on bail.

Each was charged as an adult, and originally faced felony charges of aggravated assault, conspiracy, criminal trespass and a slew of other charges.

Defense attorney Brian Manchester, who represented Brett Lahr, declined to comment about why one brother waived his preliminary hearing and the other didn't.

Manchester did say he'll be filing motions to dismiss all charges. District Attorney David Peter Johnson said he expects defense attorneys for Dylan Lahr, Porter and McGee to file to move the cases to juvenile court, but he will oppose those motions.

Prosecutors allege the four teens went on a troublemaking spree in the late night hours of July 10, ending with throwing a rock off an overpass that crashed through the window of a vehicle below.

According to testimony during Tuesday's preliminary hearing, the rock smashed into the face of Sharon Budd, a 53-year-old mother of four from Ohio. She is now in Geisinger Health South undergoing rehabilitation. She lost most of her vision capabilities and had a large part of her skull removed.

Her husband has said she's out of the life-threatening phase, but physicians are unsure of when — or if — she may regain the bodily functions she had prior to the incident.

McGee, a senior at Milton High School, testified that he and his friends had specifically planned that night to swing baseball bats at mailboxes and throw rocks at parked cars.

The evening started off with the teens driving a car through a cornfield, breaking a window of a house and then traveling to the I-80 overpass where the defendants stopped the car.

McGee said Dylan Lahr and Tyler Porter exited the car, and Dylan Lahr, using two hands, threw a rock over the overpass toward moving cars below. Then, he heard a loud crashing sound. McGee began to cry when he described that after the rock was thrown, he saw the hit vehicle pull over to the side of the road.

Inside the car were Randy and Sharon Budd, of Uniontown, Ohio, along with their daughter, 19-year-old Kaylee. Randy testified that his wife had just gotten off the phone with their older son, Luke, who is being deployed to Afghanistan, when suddenly they heard what sounded like "an explosion."

"It felt like an explosion went into the car, grenade-like, just a huge explosion," Randy Budd testified during the hearing. "I didn't know what was going on. I did look up and saw there was a hole in the windshield on the passenger side. Kaylee was screaming, 'Dad, Dad, what did I do?"

Budd said that once his daughter pulled over the car, he exited it and walked around to what had happened to his wife, calling it "the most gruesome thing that I've ever seen."

Sharon Budd had a large gash in her head, and Randy Budd said the only way he could tell his wife was breathing was because the top of her head was moving and blood was coming out.

The 911 call Randy Budd made that moment was played in the courtroom Tuesday. In it, he told operators that, "this is bad; something came right through the windshield."

"There's a rock that came in. She is grasping for her life," he said in the tape. "Oh my God, half her brain is gone. Oh my God. Oh my God."

Johnson entered the rock into evidence, noting the football-shaped rock weighs 4.63 pounds.

McGee testified that he "feels bad," and didn't expect that their late-night activities would cause harm to anyone.

"We didn't think anything of it at the time," he said. "We didn't think anyone would get hurt."

Editor's note: This story was updated to correct the name of the facility where Sharon Budd is being treated.