The suspect was identified as  Abdul Ali alias Lala.

He was arrested a day before on charges of blasphemy.

The suspect, a resident of Kharotabad, a locality on the outskirts of Quetta, was detained after a video in which he allegedly made objectionable remarks about Khatm-i-Nabuwwat (finality of prophethood) and the Holy Prophet (PBUH) went viral, reported Dawn News.

A case was registered against him after a video went viral.

An angry mob belonging to religious parties, including Tehreek-i-Labbaik Pakistan (TLP), gathered outside the Kharotabad Police Station where the suspect was initially held. The crowd demanded custody of the suspect, pelting the police station with stones and even launching grenade attacks in their protest, the newspaper reported.

Police later shifted the suspect to the Cantt Police Station for his safety.

A constable, who was posted  at the Kharotabad station arrived at Cantt and gunned down the suspect in the lock up.

The cop “suddenly opened fire on the suspect who was in the police lockup”, Inspector General Police in Balochistan Moazzam Jah Ansari told Dawn, adding that the police officer used his personal pistol.

The constable was identified as Saad Khan Sarhadi.

He has been arrested.