The boys -- a 16-year old and two 17-year olds -- are accused of sexually touching girls and using aerosol cans to make blowtorches on the bus. Police arrested them last Friday after a victim came forward.
Portage police Cpl. Troy Williams explained the students on the bus didn't come forward sooner because of fear.
"Every kid on that bus is a victim for having to endure that. It's unimaginable," Williams said.
The boys face several criminal charges including sexual battery and strangulation. All three have been suspended from school pending expulsion hearings.