KSai Deepthi, a class 9 student of the Jyothi Model School, hanged herself at her residence in the Malkajgiri area here last evening.
"We have taken three persons, including a teacher, into custody. They will be produced in the court shortly," inspector Komraiah of the Malkajgiri police station told PTI.
Besides booking the three for abetment of suicide under section 306 of the Indian Penal Code, the police also invoked the Scheduled Castes and Scheduled Tribes (Prevention of Atrocities) Act against them as the girl belonged to a scheduled caste community, the inspector added.
The girl had felt humiliated after she was asked to leave the class recently and not allowed to appear in a school examination for non-payment of fees, according to her family.
In her suicide note, she wrote, "Sorry mummy. The school did not allow me to write the exam," the inspector said.