Newly released 911 calls reveal the horror inside an Ohio high school as an alleged gunman opened fire in a bloody rampage that left three students dead and two wounded.

Russell King Jr., 17, Daniel Parmertor, 16, and Demetrius Hewlin, 16, were killed in a spray of bullets when a gunman, suspected to be 17-year-old T.J. Lane, began shooting inside Chardon High School at around 7:30 a.m. Monday.

An official said Wednesday that the teenage suspect told authorities he stole the gun he used from his uncle. A law enforcement official familiar with the case said the weapon was bought legally in August 2010 from a gun shop in Mentor, Ohio. The official said the gun was a Ruger .22-caliber Mark III target pistol.

Authorities released a series of 911 calls on Tuesday, detailing the terror inside the high school as the alleged gunman randomly shot at students in the cafeteria before classes began.

"We got shots fired ... multiple gunshots. We need to get out of here . . . Everyone's running away," a frantic woman is heard telling a police dispatcher.

At 7:38 a.m., one caller said simply, "Chardon High School. We need police up here. There's someone in the building with a gun."

Later, another caller said, "Three down in the cafeteria, we need an ambulance, too."

In other calls received by 911, students described the scene, saying there were some students lying down on the ground in blood. 

"He just pulled out a gun and started firing upon 500 kids, all in the lunchroom," said one student.

"I saw him take out two and then I was gone. I was out of there," said another.

Asked by a dispatcher if it was known what the shooter's "beef with these kids" was, another student replied, "I have no idea. It's a kid that, generally, like, I try to talk to; he's very quiet and he doesn't really talk to anyone."

Parmertor's mother, a nurse, told CBS News she was driving home from her night shift when she first heard news of the shooting at her son's school.

"I turned on the radio, and they were talking about it. I had a sick feeling in my stomach, I didn't know why," Dina Parmertor said. "And I was scared for him. I don't know why, and I just tried to call him. Nothing. He didn't answer, and I left a message: 'Danny, It's mom, call me back.'"

Later, Dina Parmertor got a call from her son's cell phone, briefly giving her a glimmer of hope.

"I thought, 'Oh, he's calling me,'" she said. "[But] It was commotion and it was some fire chief or something, I don't know, and he said, 'Danny is being life-flighted to Metro hospital right now. You have to go to Metro.'"

Dina Parmertor said she wanted to talk to her son, and was told that rescuers were performing CPR on him at the time.

"I said, 'Don't go, Danny, don't go,'" the mother said she told Daniel down the phone line.

The teen was airlifted to MetroHealth Medical in Cleveland, but died there along with 17-year-old King, who was pronounced brain dead at 12:42 a.m. local time Tuesday. Another student, Demetrius Hewlin, also died from his gunshot wounds at the same hospital Tuesday morning. Two other students were injured in the shooting.

Reports have since surfaced that Lane was a troubled teen who had been exposed to bullying.

Dina Parmertor said her son was "a funny, loveable kid who would help you with anything."

"He was 16 years old. He doesn't get to live his life. It was taken. He didn't do anything to anybody. He just didn't deserve it," she said.

"I know my life will never be the same again," her husband Bob added. "I will get better, but right now, I'll never be, there will always [be] something missing."

In his first court appearance Tuesday, Lane was ordered to remain in custody for the next 15 days. The teenager, a student at a nearby school, will likely be tried as an adult for three counts of aggravated murder in addition to other crimes.

Click for more on the 911 calls from Fox 8

Newscore contributed to this report.