The Milton Intermediate School fifth-grader was referred to juvenile authorities on a felony bomb scare charge. He was being held at the Rock County Juvenile Detention Center in Janesville, police said.
The school bus was full of students and parked in a lot at Milton Intermediate School shortly before 9 a.m. Wednesday when the bus driver saw a student on the bus who had a device that resembled a bomb, police said.
The bus driver said he heard the boy say that he had a bomb and that the boy "threatened to detonate the device either on the bus or in the school," according to a news release from the Milton Police Department.
The bus driver removed students from the bus, told the boy to stay on the bus and then called Milton police. School administrators evacuated the school, sending students to Milton Middle School as police surrounded the bus.
Officers called in a SWAT team from the Rock County Sheriff's Office and a bomb squad from the Winnebago County Sheriff's Office in Illinois. SWAT team negotiators coaxed the student away from the device and off the bus, taking the student into custody without incident by about 11 a.m., police reported.
The bomb squad removed and destroyed the device, which police said was a handheld video game with wires and batteries attached. There were no explosives on the device, police said.
Officers and school district administrators searched the school and found nothing suspicious, police said.
The student had been upset with teachers at the school, Milton Police Lt. John Conger said.
It wasn't clear Wednesday when the student would appear in court.
Superintendent Bernie Nikolay said school officials had not spoken to the boy since the incident, but he said the student does not have a history of threatening behavior.
"This was very out of character. He hadn't made threats prior to today," Nikolay said.
No students were harmed in the incident, which ended at about noon, Nikolay said. During the incident, the district used an electronic call system to contact parents of evacuated students, allowing parents to pick their students up at the middle school.
No other schools in the district were affected, and classes were expected to resume as usual today, Nikolay said.