Afemale student in northern Nigeria was killed by a mob who stoned, beat and set fire to her for allegedly posting a blasphemous statement against the Prophet Mohammed, according to police.

The girl, Deborah Yakubu, was surrounded by fellow students and attacked on Thursday, a police statement said.

The incident happened at the Shehu Shagari school in Sokoto, northwestern Nigeria, and the school was immediately closed.

“Students forcefully removed the victim from the security room where she was hidden by the school authorities, killed her and burnt the building,” police spokesperson Sanusi Abubakar said in a statement released to CNN.

Sokoto state’s Governor Aminu Tambuwal issued an order to close the school and directed the Ministry of Higher Education and security agencies to investigate the incident.

The video, which circulated on social media in the aftermath of the killing, appears to show her attackers holding a matchbox and celebrating after setting her alight.

CNN has not been able to independently verify the video.

Two people have been arrested and “the suspects in the viral video on Twitter were spotted and will be nailed soon,” Abubakar added.

Religious tensions

Nigerians have expressed their outrage on Twitter and denounced the killing. There are fears it could heighten sectarian tensions in the country, which is largely split along religious lines, with the north majority Muslim and the predominantly largely Christian.