A student opened fire in a high school cafeteria in Ohio, fatally wounding one classmate and injuring four others before fleeing and eventually giving himself up, police said.
Two gunshot victims lay in hospital in a critical condition as the small town of Chardon, near Cleveland, struggled to come to terms with being thrust into the media spotlight of America's latest school shooting tragedy.
Fellow students described the gunman as a 17-year-old "outcast" who had suffered bullying and said he had posted warnings on Twitter and left disturbing messages on Facebook.
Children were preparing for class at Chardon High, when the gunman, identified by police as a "juvenile," started shooting with a handgun shortly after 7:30 am (1230 GMT) on Monday, apparently targeting one group in particular.
Panicked students, taken by surprise as they were eating breakfast and waiting for first period to start, screamed and sprinted out of the cafeteria, fearing for their lives.
"My friends were crawling on the floor, and one of my friends was bent over the table, and he was shot," one boy, Nate, told the Cleveland Plain Dealer. "It was almost like a firecracker went off. I turned around and saw him standing with a gun and I saw him take a shot."
A teacher eventually chased the shooter from the school, as the town of 5,000 residents was placed on lockdown and the victims were rushed to hospital, some by helicopter.
The suspect was apprehended by police a short while later after turning himself in to bystanders, but it soon emerged that one victim, 16-year-old Daniel Parmertor, had died in hospital.
"We have one deceased student right now," Chardon police chief Tim McKenna told a press conference. "That's the sad news for all of us today."
"One of the teachers happened to chase the shooting suspect out of the building," allowing officers to secure the school to allow emergency personnel to treat the victims, he said.
"With that done, we started searching the areas, and shortly thereafter, we came up with the suspect. He is in custody," McKenna said. "No name will be released because he hasn't been charged yet. He is a juvenile."
The FBI was helping the sheriff's department search the suspect's home.
Earlier, masked SWAT teams had ringed Chardon High, conducting security sweeps so that pupils could safely be evacuated from the building and transported to a nearby elementary school to be released to parents.
"We are shocked by this senseless tragedy," said a statement from the Parmertor family. "Danny was a bright young boy who had a bright future ahead of him. The family is torn by this loss."
Word of the shooting sent fearful parents rushing to the school, where they went through a protracted process of being reunited with their children.
"We've had disaster drills in the past, thank God we put those into place because our teaching staff did an excellent job in a very horrible, traumatic experience this morning," said Chardon schools superintendent Joe Bergant.
"We feel so disheartened -- it's going to take me a moment to get back together here. We certainly hope those families know that they're in our thoughts and our prayers."
Chardon resident Karen Porter said the shooting was out of character for the small, close-knit community. "This is hometown USA in the best sense of the word. It's not what you'd expect at all.
"This is so sad on so many levels," she told AFP. "I feel sorry for the kids that were injured, that's such a tragedy. The kids that witnessed the shooting will be forever changed."
Porter's sympathy extended to the suspect. "To come to that part where you even think about taking somebody's life, much less to do it, it's too much to think about."
A candlelight vigil service was scheduled for Tuesday night at a local church and grief counselors were on call to help the small-town Ohio community to deal with the traumatic event.
Announcing that classes on Tuesday would be canceled, Bergant added: "I hope every parent, if you haven't hugged or kissed your kid in the past few days, takes that time."
The last major school shooting incident in Ohio was in Cleveland in 2007 when a 14-year-old student killed himself after wounding two teachers and two fellow students.
The deadliest school shooting in the United States was the 2007 massacre at Virginia Tech University that left 33 people dead. The worst high school shooting was in 1999 at Columbine High School in Colorado when two students killed 12 fellow students and a teacher.