The killers poured kerosene over Nusrat Jahan, 18, and set her on fire on the roof of her madrasa in April in the southeastern district of Feni. Police said in their charge-sheet the murder was carried out on the orders of the principal.

"The judgment proves that no one is above the law," public prosecutor Hafez Ahmed told reporters after the court verdict.

He said the defense lawyers had tried unsuccessfully to establish that Jahan had committed suicide.

Defense lawyer Giasuddin Nannu said his clients will challenge the verdict in the High Court.

Jahan's death sparked public outrage and mass demonstrations calling for her killers to be punished. She had faced pressure to withdraw a complaint to police in March accusing the school principal of attempted rape, her family said.

Prime Minister Sheikh Hasina had met her family and vowed to bring the killers to justice.

"I can't forget her for a moment. I still feel the pain that she went through," mother Shirin Akhtar said as she burst into tears at her home following the verdict.

Jahan's brother, Mahmudul Hasan Noman, demanded that the death sentences be carried out swiftly and sought protection for his family against reprisals.

"We live in fear. We were threatened even today in the courtroom," Noman said.

Bangladesh has seen a dramatic rise in the number of rape cases in recent months, with 217 women and children raped in September, the highest in any single month since 2010, according to a report published by Bangladesh Mahila Parishad, a women's rights group.

Many more cases go unreported because women fear being stigmatized. Rights activists attribute the increasing number of rapes to a lack of awareness, a culture of impunity, moral decadence, and people of influence protecting suspected rapists for political reasons.

REUTERS