A teenage Rohingya girl, who was adopted by a Bangladeshi family, was killed at her house in Teknaf upazila on Friday night.
Asma Akhter, 16, and her father Sharif Uddin were residents of Balukhali Rohingya camp.
Locals said Saudi expatriate Syed Alam's wife Hasina Akhter was also seriously injured in the attack.
Hasina and her adopted daughter Asma lived in their house at Chakmarkul under Hoaikkong union.
Unidentified assailants entered the house around 9:00pm and stabbed the mother and daughter several times before fleeing.
Hearing their screams, their relative Shahina Akhter shouted for help. Locals came to the scene and rushed the two to an NGO-run hospital in Goyalmara area in Ukhia upazila where doctors declared Asma dead.
Critically injured Hasina is undergoing treatment at the hospital. Alam and Hasina's only child Asma was a student at a residential madrasa in Cox's Bazar.
On information, Additional Superintendent of Police (Ukhia Circle) Nahid Adnan Tahian along with other officials visited the spot.
Asma's body was sent to Cox's Bazar Sadar Hospital, police said.
“We are investigating,” he added.