CHARDON, Ohio — The fatal shooting rampage in a high school in this quiet suburb of Cleveland remained a puzzle on Tuesday, with prosecutors saying that a student had confessed to the killings and had told them that he did not know his victims and chose them at random.

Prosecutors said the student, T. J. Lane, 17, admitted taking a .22-caliber Ruger semiautomatic pistol to Chardon High School on Monday and firing 10 rounds at four students at a cafeteria table. He has not been formally charged, but prosecutors said it was likely that he would be tried in an adult court.

Three of the victims — Russell King Jr., Demetrius Hewlin and Daniel Parmertor — have died. Two others were wounded. One has been released from the hospital.

“This is not about bullying, this is not about drugs,” said David P. Joyce, the Geauga County prosecutor. “This was an effect of one lone gunman. He chose his victims at random.”

Mr. Lane appeared in court for the first time on Tuesday, wincing as the prosecutors read the accusations against him. Dressed in a crisp khaki-colored shirt and dark low-slung pants with a thick belt, he sat in a wooden chair with his back straight, speaking in barely audible tones to the judge, Timothy J. Grendell, in Geauga County Juvenile Court. His face crumpled briefly into tears as he was led away, and he appeared to whisper the words “I am so sorry” to two aunts and his grandfather, Jack Nolan, who is also his legal guardian.

The authorities have until Thursday to charge Mr. Lane.

The day brought more questions than answers to this blue-collar town of 5,000 east of Cleveland. Mr. Lane is a sophomore at Lake Academy, an alternative high school for at-risk youths, some of whom take a bus from Chardon High School. Students interviewed at both schools described him as quiet but friendly, and interested in Nascar and hunting.

CNN reported on Tuesday that Mr. Lane had taken the gun from a family member, who had bought it legally, but Mr. Joyce said he could not confirm that.

“By all accounts, T. J. is a fairly quiet and a good kid,” said Robert N. Farinacci, the Lanes’ lawyer, who added that he had not been in trouble before.

David Rafail, 17, of Willoughby, Ohio, a student at a vocational school next to Lake Academy, said he used to take smoking breaks with Mr. Lane. He called him a quiet student who “was always alone.”

Jarod Mausolf, 17, a student at Lake Academy, said he had taken American history with Mr. Lane and called him a good student, though far more quiet than most.

“He never talked at all,” Mr. Mausolf said. “The expression on his face, it was sad. A sad face. Kind of blank.”

Another student, Damien Stewart, 16, a sophomore at Lake Academy, said he had an English class with Mr. Lane.

“He was pretty cool,” Mr. Stewart said. “Very quiet. Nobody really talked to him. Not because we didn’t like him, he just wasn’t a talker. He was very sweet, very nice, very friendly.”

Mr. Lane’s lawyer said the teenager had no prior trouble with the law. Mr. Lane’s father, Thomas Lane, was arrested in 2002 on charges of attempted murder, and a restraining order was imposed forbidding him to contact his former wife, according to court records. Mr. Lane struck a plea bargain for a lesser charge and was sentenced to four years in jail. He served nine months of his sentence and was released in June 2003.

The families of Mr. King and Mr. Hewlin issued statements on Tuesday that included a note of pride that their sons would be able to help others through organ donations. “We ask that Russell be remembered for who he was, a strong boy with a big heart,” the family of Mr. King said.

Mr. Hewlin’s family described him as a “happy young man who loved life and his family and friends.”

Joseph Bergant II, the superintendent of schools, said Chardon High School would reopen on Friday. Parents and students were invited to the school on Thursday to meet with counselors.

“We’re not just any old place, Chardon,” Mr. Bergant said “This is every place. As you’ve seen in the past, this can happen anywhere.”

Though prosecutors said Mr. Lane had selected victims at random, some students at the school presented a different account. One of them, Nate Mueller, said Mr. King had recently started dating Mr. Lane’s ex-girlfriend, according to The Associated Press.

Hundreds of people packed the Church of St. Mary on Tuesday night, with several thousand more outside, holding candles, singing and remembering those who died with prayers. Among the speakers was Ohio’s governor, John R. Kasich.

A tape of 911 calls, which was released by the police on Tuesday, paints a picture of panic that spread through the school as soon as Mr. Lane fired his first shots around 7:40 a.m. in the cafeteria. A caller told the dispatcher that he had seen students lying on the ground with blood around them.

“What was his beef with these kids, do we know?” the dispatcher asked. The caller responded: “I have no idea. It’s a kid that, generally, I try to talk to. He’s very quiet, and he doesn’t really talk to anyone.”

Prosecutors offered a similar picture. When they entered the school building, they found three unconscious male students bleeding from the head, and another one in a hallway bleeding from the neck. A female student, identified by the local news media as Joy Rickers, was also wounded but was released from the hospital on Tuesday. The police said that they found Mr. Lane about an hour later, around 8:40 a.m., on Wooden Road, and that he was detained without incident.

Christine Savides, a junior at Chardon High School, said she knew Mr. Lane in middle school and described him as a “teen therapist” for his ability to listen to others’ troubles.

“He was always there for you if you ever needed to talk,” she said, standing outside Chardon Middle School.

She said that Chardon had hunting enthusiasts and that guns were not that uncommon, but that no one expected anything like this.

“Here in Chardon, we’re out here in the woods and we’re all gung ho for doing any fun activity,” she said. “We’re all hunters and we all have fun, and it’s just unfortunate that something like this would happen here.”