JACKSONVILLE, Fla. -- A tractor-trailer driver was on his cell phone when he slammed into a school bus in north Florida, police said Wednesday. A 13-year-old girl died, but officials are crediting heroic passers-by who pulled students off the burning bus with preventing an even bigger tragedy.

There were 21 students on the bus when 30-year-old Reinaldo Gonzalez's truck rear-ended it Tuesday, police said. Both vehicles caught fire.

"This was a tragedy, but it's also a miracle," Marion County Superintendent of Schools Jim Yancey told the Ocala Star-Banner. "We're lucky one person got out of there alive."

Yancey said at least four bystanders helped students off the bus. One of those bystanders was a Jacksonville man named James Horton.

"I haven't been able to eat at all. I keep hearing screams," Horton told Channel 4.

He said he still hears the screams of the children caught on the school bus.

Horton, a trucker and a father of three, said he just happened to be passing by when a tractor-trailer crashed into the back of the stopped school bus.

"I freaked out. I couldn't believe it. I was shocked," Horton said.

Still, Horton said he never hesitated as he ran onto the bus and started getting children off the burning vehicle.

"The fire was bad. The smoke, you couldn't even see anything. We were just feeling and they were handing them back and searching for more and we couldn't find anymore," Horton said.

Horton said he was traveling in the opposite direction and locked up his brakes and skidded off the side of the road.

"There wasn't time to think, just time to grab and get. The last two children we got off there were in pretty bad shape. All we could do was get them off. Once we got off the bus, it just burst into total flames," Horton said.

While Horton's efforts likely helped save lives, he told Channel 4 he doesn't much care for the word hero.

"I'm not a hero. I consider myself lucky to be there when it happened. God put me there for a reason," Horton said.

Horton and the three other rescuers who had done so much were visibly grieving for the one student they couldn't help.

"The kid was lodged and I just couldn't get her out," said Chris Mann, an elevator installer who also stopped to help. "There was nothing I could do."

The Florida Highway Patrol identified the student killed as Frances Schee. She was apparently trapped inside the burning bus.

"It was very hot. It smelled really bad, and I was scared because I couldn’t get off and the fire was just coming," said Natalya Mitchell, a seventh-grade student who was on the bus at the time of the crash. "All we saw was a big truck come and hit -- and the fire."

The girl said she knows she's fortunate to be alive, but said she couldn't believe her friend Frances is gone.

"I wanted somebody to help her, but nobody really could," Mitchell said.

Grief counselors were at several Marion County schools on Wednesday morning, meeting with students and faculty.

One of Frances' teachers remembered her for her positive spirit.

"At the end of the day, I would see Frances and she would smile and she would have something wonderful to say," Sarah Netwood said. "She was very popular. She’s the kind of student that all teachers wanted to have."

Frances was involved in several school activities, including playing clarinet in the school band.

"It is just a really sad day for Marion County schools," Yancy said. "Those 18 kids who got out of there alive are very fortunate to get out of there alive. This is a tragedy but it is also a miracle."

A funeral service for Frances will be held at Jarvey Grant Park on Sunday at 10 a.m.