Action taken within few hours of video of the gruesome act going viral on social media
Reportedly 16-year-old Rabia had refused to marry her teacher 26-year-old Nasreen's brother in Karachi
Police register case on complaint of victim's family
Family of deceased boy refused to lodge a case, but police itself registered a murder case on behalf of state
Cleric lost his temper when boy said he could not attend seminary classes a day ago because he was fasting
Incident took place at a religious seminary in Sherzaman Colony on March 29