This kind of thing happens because Pakistan's blasphemy laws give some the idea that they can act against Christians with impunity. "Pakistani Police Allegedly Make Threats after Murdering Christian," from Compass Direct News, January 18:

KARACHI, Pakistan, January 18 (CDN) -- Pakistani police are threatening the father of an 18-year-old Christian man whom officers raped, killed and threw into a sewer last week, according to area Christians.

Christian residents of Akhter Colony, Karachi who pulled the body of Waqas Gill from the sewer on Jan. 11 protested an alleged police cover-up by placing the corpse in the middle of a street and chanting slogans against officers of Mehmoodabad police station. They said local officers kidnapped and sodomized Gill before shooting him dead on Jan. 9.

The victim's father, Pervez Gill, told Compass that four policemen on Jan. 6 abducted his son without a warrant and without making any charges. He said higher level police officials took notice of their Jan. 11 protest and reluctantly filed charges against the four policemen, two of them identified as Muhammad Amir Butt and Muhammad Adeel Khatak of the Mehmoodabad police station in Jamshaid Town, Karachi. The First Information Report is No. 38/11 under the murder laws of Section 302 of Pakistan Penal Code.

"Police are now threatening us and other Christians of Akhter Colony that we have to retract the charges," Gill said, nearly in tears. "Police registered a case against the culprits, but they have not filed it under the proper parts of the section, which weakens the case, and police have done everything possible to save their fellow policemen."

Gill said this police bias was the reason the other two officers named were still at large, with no action taken against them.

Local Christian protestors said Muslim policemen unduly delayed an autopsy to protect fellow officers, on the assumption that Christians were socially and financially weak in the predominantly Sunni Islamic country. After the Jan. 11 protest, however, an autopsy was undertaken and showed that Gill was subjected to sexual assault, tortured, shot dead with police revolver bullets and thrown into a waste drainage line, they said.

Sources said at least six other area Christian youths had been similarly killed.

"I don't expect any justice from the investigating officers of the same police station whose police constables kidnapped, sodomized and snatched the life of my son," Gill said.

He said that police have threatened to kill them or charge them with false crimes if they do not withdraw the charges against the officers. Under Pakistan's "blasphemy" laws, insulting Muhammad, the prophet of Islam, is punishable by death....

Christian Legislator Tahir Naveed Chaudhary condemned the killing, stating that Sindh Province police have started to imitate Punjab Province police's discrimination and delays in autopsies and filing of charges against those who attack Christians.

"Day by day, crimes against Christians are increasing, and rape or abuse of Christian women and girls has become a commonplace thing," Chaudhary said. "Life of any of the Christians at any place in Pakistan is not safe."