A bang, then blood and chaos. Students describe terror that unfolded in Kentucky school.

The first warning of trouble many students had during the deadly shooting at a Western Kentucky high school Tuesday was a pop that some mistook for a balloon bursting, but the scene turned to hell in seconds, according to several who were there.

The 15-year-old boy charged in the shootings appeared to pull the trigger randomly, setting off a panicked scramble to get out of Marshall County High School, students said Wednesday.

Students screamed and ran, leaving behind backpacks, purses and cellphones.

The boy accused of shooting ran to a room in the school and talked with other students as if nothing had happened, one student told the Herald-Leader.

Two 15-year-old students died from gunshot wounds and more than a dozen others were wounded. In addition, several students were hurt in the rush to escape.

Sydney Temple, a sophomore who was within feet of the boy who fired the shots, said she saw a male student with a bullet lodged in his ribs and blood pouring out.

“It was horrifying,” she said.

Kentucky State Police revised the number of victims to 20. Bailey Holt, who died at the school, and Preston Cope, who died at a hospital were among 16 shot.

Kristin Smart, spokeswoman for Vanderbilt University Medical Center, said Wednesday that one wounded girl was released Tuesday evening and that the conditions of three of four male students had been upgraded to stable. A fourth was still listed in critical but stable condition.

Police arrested the alleged shooter within minutes. Investigators have not released his name because he is a juvenile.

He has been charged with two counts of murder and authorities plan to add a dozen counts of first-degree assault, assistant Marshall County Attorney Jason Darnall said Wednesday.

Assault and attempted murder charges have the same penalty, and prosecutors feel the case for assault charges is stronger, Darnall said.

Darnall said at a brief news conference that prosecutors will seek to have the 15-year-old tried as an adult. A judge would have to approve that request.

If that happens, police and prosecutors are expected to present evidence to a grand jury Feb. 13.

Police spent much of the day Wednesday at the closed high school continuing to collect evidence and documenting the shooting scene, but authorities did not release new details about the investigation, including a possible motive for the shootings.

There was talk around the county seat of Benton and in Draffenville, the community nearest the school, that the alleged shooter had been bullied, but several students told the Herald-Leader they had not seen him bullied at school.

Students who had classes with the alleged shooter said he was quiet and kept to himself, was a member of the band, did what he was asked to do in class and did not cause discipline problems that they knew about.

“He was never rude to anybody,” said Gracie Ray, a sophomore.

Darnall, who was at the school to assist police, said his wife, Jenny, teaches at the school and helped students evacuate, but she did not want to talk about the shootings.

“It’s hard for us all to talk about,” Darnall said.

But some students said they couldn’t help playing the shooting over and over in their minds.

The 15-year-old allegedly unleashed a barrage of gunshots from a pistol a few minutes before classes were scheduled to start.

The shootings took place in a large, open area in the center of the school called the “commons,” where students gather at that time of day to talk and eat breakfast.

There were hundreds of students in the area when the boy started shooting, said Ray.

Ray was talking with her friends Ashlynn Kegel, a junior, and sophomore Haley Swift, in the commons.

Ray said she heard one bang, then a pause.

“Then it just started going one after the other,” she said. “I just remember thinking every shot I heard was somebody’s life.”

Swift said she knew the first bang sounded like a gunshot, but it was hard to immediately comprehend because it’s not a sound that’s supposed to happen in school.

“It was like you knew it was a gun, but I was like, ‘It’s not a gun,’” Swift said.

The grim reality hit quickly. Within seconds, students started screaming for people to get out of the building and hundreds of students ran.

Swift said she heard a teacher scream for students to run.

People slipped in spilled soft drinks and coffee, tripped over other students and lost shoes.

“People were trampling over the top of each other,” Kegel said.

There were acts of heroism as well. Students helped each other up after falling; Kegel and Swift said they fell and friends helped them up.

Ray said a boy she knows shielded a friend who had been shot, even though he also was wounded.

Marshall County Superintendent Trent Lovett thanked his staff, administration and students Wednesday afternoon for a “phenomenal” way of handling the situation.

“(There were) several acts of heroism. I’m very proud of them,” Lovett said.

Temple said she closed her eyes, got down and started praying when the shooting started. She was so close she heard the clip fall out of the gun; that’s when she got up and ran.

“I was freaking out. I just sprinted out of the school,” she said.

Temple went to a guard shack outside. A boy came in and said “Look at this,” and lifted up his shirt to show he’d been shot in the abdomen, she said.

“I didn’t know what to do at all,” she said. An administrator soon came and took the boy for help.

Temple said she did not see the boy fire the shots, but a friend who did told her he was just swinging the gun around randomly.

Jason Thompson, a sophomore, said he was in the commons and saw the alleged shooter point a black gun at another boy. Thompson first thought the shooter was playing a joke and that the gun was perhaps a pellet pistol, but then heard the shot and saw the muzzle flash.

“From there it was just chaos,” he said.

Thompson grabbed his girlfriend’s hand and got her out of the school.

Another witness, junior Clayton Edwards, said he had just gotten an iced coffee when the boy started shooting.

He said he saw the boy pull the gun from a satchel from about 10 feet away, but the shooter had his back to Edwards.

The boy didn’t say anything as he shot, Edwards said.

“Thank God he didn’t see me,” Edwards said. He said he hid between two vending machines at one point.

A student who witnessed the shooting, Bryson Conkwright, told WKRN he was just 4 feet away from the boy.

The shooter looked lifeless and didn’t think twice about what he was doing , Conkwright told WKRN

“You could tell he wasn’t thinking about it,” he said. “He didn’t pause. He didn’t hesitate. He pulled it out and he just did it. He didn’t care. Something happened to him. He was...I don’t get it. Something happened to him that made him want to do that.”

After the shooting stopped, Edwards said he went to a room inside the school and the shooter was there, talking to friends “like it was nothing.”

Police said they found what is believed to be the gun used in the shootings, but it was not with the boy.

Edwards said he saw police arrest the boy. Officers asked if he had anything that could injure them, and he said he had some knives, Edwards said.

The boy did not resist police, he said.

Once outside the school, some students tried to flee in cars and trucks, with some getting stuck in a field by the school, but hundreds fled on foot.

Another student, Tristan Cline, told CBS News he found one of his friends 50 yards away laying in a field after being struck by a bullet. Cline rushed his friend to the hospital.

“One of my teachers, Dan Langhi, and my assistant principal Brent Lovett, helped me get him to my car,” Cline said. “He was shot in the shoulder and was scared and no one knew what to do. I took him in my car and drove as fast as I could.”

Many went into nearby businesses and a Christian school for refuge.

Mark Garland, who owns a business next door to the school called ServiceMaster of the Lakes, said two dozen or more students came into his building. Some seemed to be in shock, he said

“They just looked overwhelmed,” Garland said.

One girl was trying to talk but couldn’t. Garland had her sit down and covered her with a blanket.

It took a couple of hours for parents to pick up all the students.

Many businesses in Benton and Draffenville had signs up condolence and support Wednesday.

“Prayers for strength and healing,” said the one at the Ponderosa Steakhouse.

Swift said she could not get the sound of sirens out of her head Tuesday night, and some students said it is going to be hard to go back to the school.

"I just feel like I'm just going to replay it every time I'm in there," Temple said.

"You're always gonna just be like looking over your shoulder to make sure everything's okay," Swift said.

But they know they'll have to face that fear.

"We're going to have to deal with it and cope with it and just be strong and be there for each other," Kegel said.

Mike Stunson: 859-231-1324, @mike_stunson

Related stories from Lexington Herald Leader