The victim's parents hail from Kanpur in Uttar Pradesh and have been living in Bangalore for several years.
Her father works for a pharmaceutical firm and her mother is a housewife.
The police said the incident came to light on Monday evening when the victim came home crying. When her mother asked the child what had happened, she said she had been sexually abused by Sabanna. The next morning, the mother went to the school with her relatives and friends to complain to the school management.
Though the school authorities initially denied the incident, they sacked Sabanna after the victim's family insisted.
"Later, a formal complaint was filed by the mother and based on it Sabanna was arrested. He has been booked for attempt to rape and other charges. Both the victim and the accused were sent for medical tests," Bangalore police commissioner BG Jyotiprakash Mirji said.