T.J. Lane, 17, admitted taking a .22-caliber pistol to Chardon High School along with a knife and firing 10 shots at a group of students sitting at a cafeteria table Monday morning, Prosecutor David Joyce said.
The hearing came hours after the death toll rose to three, and as schoolmates and townspeople grappled with the tragedy and wondered what could have set the gunman off -- a mystery the court appearance did nothing to solve.
"He did not know the students but chose them randomly," Joyce said.
Lane's face twitched lightly while the prosecutor recounted the attack, and the slim young man sniffled and half-closed his eyes as he walked out of the room with sheriff's deputies.
Lane's grandfather, who has custody of the teenager, and two aunts joined him in court; the women reached over and lightly embraced the grandfather as the hearing began.
Judge Timothy Grendell ordered the boy, who is considered a juvenile, held for at least 15 days. Prosecutors have until March 1 to charge him.
The judge imposed a gag order on opposing attorneys at the prosecutor's request and told the media not to photograph the boy's face in court.
Meanwhile, shaken residents offered condolences and prayers to the families of those killed and wounded at the 1,100-student high school. All three of the dead were students, as are the two wounded victims.
"This gets more tragic, the whole area is suffering, our prayers go up to God to give all strength, healing and closure," said one of hundreds of Facebook postings on a memorial page.
The community offered grief counseling to students, staff and others at area schools.
"We're not just any old place, Chardon," Chardon School Superintendent Joseph Bergant II said. "This is every place. As you've seen in the past, this can happen anywhere, proof of what we had yesterday."
A Cleveland hospital said Demetrius Hewlin, who had been in critical condition, died Tuesday morning. The news came shortly after Police Chief Tim McKenna said 17-year-old Russell King Jr. had died.
Another student, Daniel Parmertor, died hours after the shooting, which sent students screaming through the halls and led teachers to lock down their classrooms as they had practiced doing so many times during drills.
Both King and Parmertor were students at the Auburn Career Center, a vocational school, and were waiting in the Chardon High cafeteria for a bus for their daily 15-minute ride when they were shot.
The police chief would shed no light on a motive.
"I feel sorry not only for that family but all the families that are affected by this," McKenna said. Characterizing himself as a "hometown boy," he added: "Chardon will take care of Chardon."
A student who saw the attack up close said it appeared that the gunman targeted a group of students sitting together and that one of the dead was shot while trying to duck under the cafeteria table.
Lane's family is mourning "this terrible loss for their community," attorney Robert Farinacci said in a statement.
Lane did not go to Chardon High, instead attending nearby Lake Academy, which is for students with academic or behavioral problems.
Fifteen-year-old Danny Komertz, who witnessed the shooting, said Lane was known as an outcast who had apparently been bullied. But others disputed that.
Farinacci, representing Lane and his family, told WKYC-TV that Lane "pretty much sticks to himself but does have some friends and has never been in trouble over anything that we know about."
Student Nate Mueller said that he was at the table in the cafeteria where the victims were shot, and a bullet grazed his ear.
"My friends were crawling on the floor, and one of my friends was bent over the table, and he was shot," Mueller told The Plain Dealer. "It was almost like a firecracker went off. I turned around and saw (Lane) standing with a gun and I saw him take a shot."
Mueller told the Cleveland newspaper that Lane would wait at the school to take a bus to Lake Academy. Mueller said that King -- one of those killed -- had recently started dating Lane's ex-girlfriend.
Lane "was silent the whole time," Mueller said. "That's what made it so random."
Frank Hall, an assistant high school football coach who students say chased the suspected gunman out of the cafeteria, told a Cleveland TV station that he couldn't discuss what happened, but added: "I just want to say that I'm sorry for the families."
"I wish I could have done more," said Hall, whom students have hailed as a hero.
AP writers Dan Sewell in Cincinnati, Julie Carr Smyth and Andrew Welsh-Huggins in Columbus, and photographer Mark Duncan in Chardon contributed to this report.