Insulting Islam is punishable by death under Pakistan's blasphemy laws.
Area Police Chief Ijaz Ahmed said four policemen were slightly injured Monday when protesters attacked the station near Sheikhupura city, about 50 km west of Lahore, the capital of the eastern province of Punjab province.
The trouble began hours after the villagers turned a local resident over to police, claiming he had torn pages from the Quran and thrown them on a road.
However, officers freed the man "after determining that he was a drug addict, and had no idea what he had done," Ahmed said.
He said the release angered villagers, who attacked the police station, blocked a main city road, and held a protest rally.
The villagers "are demanding action against those officers who freed" the man, he said, adding that authorities were negotiating with protesters --and that efforts were underway to find and arrest the man.
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