An 11-year-old boy is in custody after Orange County deputies said he stabbed a 15-year-old boy with scissors at Chain of Lakes Middle School, near Windermere. Deputies believe they now know what caused the stabbing.

Deputies said the teen, an eighth-grader at the school, on Conroy Windermere Road near Apopka Vineland Road, was in the bus loop outside the school Wednesday morning, when he was stabbed in the chest area by a sixth-grade student as the two were getting off the bus.

The sheriff's office said the two students were fighting over a cell phone on the school bus. When they got off the bus, deputies said the victim hit the suspect twice in the head. They said that's when the suspect pulled the scissors from a pocket and stabbed him.

The student was taken to Arnold Palmer Hospital for Children, in Orlando. Deputies said he was alert as he was transported and his injuries were not life-threatening.

No lockdowns were ordered at the middle school, and FCAT testing there got underway as scheduled, deputies said.

School officials said testing is back to as normal as it can be after what could be a major distraction for other students.

"Today is a testing day, FCAT," said Dylan Thomas, with Orange County Public Schools. "Middle schools -- all three grades -- are taking the test, so we are trying to maintain a normal day."

The school district notified parents through an automated voicemail and mobile app, alerting them to what happened.

One father said he is pulling his son from riding the bus to school, because he's afraid something like this could happen again.

We will not identify the 11-year-old suspect unless he is charged as an adult. Please read our Crime Guidelines for more information.