A madrasa girl suffered severe burns as stalkers threw acid at her when she was studying in her room in the district's Mithapukur upazila on Wednesday night.
The victim, Dipa Rubaiya Ritu, 15, the daughter of Dulu Sarker of Gopinathpur village, is a class-X student of Bhandabari Dakhil Madrasa in the upazila.
She was first taken to Mithapukur Upazila Health Complex and later shifted to Burn and Plastic Surgery Unit of Rangpur Medical College Hospital.
MA Hamid, registrar of the unit, said right side of her face and right ear were burnt in the attack.
Quoting the victim's family, police said Ritu was studying in her room in Gopinathpur village around 9:30pm and windows of her room were open. The stalkers hurled acid at her through the windows.
Victim's elder brother Rajibul Islam said hearing her sister's screams, they entered her room, rescued Ritu and took her to Mithapukur Upazila Health Complex on that night.
Ritu's mother Lutfun Nessa said some stalkers of Gopinathpur village, including Ashraful Islam, a classmate of her daughter, used to tease Ritu on her way to madrasa.
On Wednesday afternoon, Ashraful also sent an indecent SMS to Ritu's mobile phone, she added.
Lutfun claimed that Ashraful had hurled acid at her daughter and demanded exemplary punishment for Ashraful.
Victim's father Dulu Sarker filed a case with Mithapukur Police Station in this connection.
Humayun Kabir, officer-in-charge of the police station, told The Daily Star that police arrested Ashraful at Gopinathpur Bazar yesterday morning.
Ashraful would be interrogated, the police official added.