A Pakistani police officer today killed a man who had been brought in on charges of blasphemy, police sources said.

The victim, who was Muslim, was arrested on Wednesday in Quetta, the capital of Balochistan province, after a video of him went viral and a case was filed against him.

A crowd of 200 youths then attacked the police station where the suspect had been taken, and authorities were forced to move him to another. There “an on-duty police officer attacked him inside his cell and killed him,” Balochistan police chief Moazzam Jah Ansari said.

“We arrested him and he was charged with murder,” he added.

Blasphemy is a charge that inflames passions in Pakistan’s deeply conservative, Muslim society. Even unsubstantiated claims of insulting Islam and the Prophet Muhammad can lead to murders and lynchings. Human rights activists say the blasphemy charge is often used by some for revenge and that minorities are the main target.

The governor of Punjab province was assassinated by his bodyguard in 2011 after he proposed amending strict blasphemy laws.